feat: enhance authentication flow with new password management and signup components

- Introduced PasswordFieldBlock component for improved password input handling, including visibility toggle and strength evaluation.
- Added SignupCredentialsFields component to streamline user signup with email availability checks and password confirmation.
- Updated FlowChallengeForm to integrate new components, enhancing user experience during authentication.
- Refactored CSS styles for consistent design across authentication components, ensuring a cohesive look and feel.

app/globals.css

@@ -1056,6 +1056,7 @@ html[data-route-scope='drive'] body {
   border: 0;
   border-radius: 9999px;
   overflow: hidden;
+  appearance: none;
   font-size: 0.875rem;
   font-weight: 600;
   line-height: 1;
@@ -1063,14 +1064,15 @@ html[data-route-scope='drive'] body {
   color: #fff !important;
   text-decoration: none !important;
   text-shadow: 0 1px 3px rgb(0 0 0 / 60%);
-  background:
+  background-color: #050505;
+  background-image:
     radial-gradient(circle at 15% 25%, rgb(255 255 255 / 70%) 0, rgb(255 255 255 / 70%) 0.45px, transparent 1px),
     radial-gradient(circle at 62% 18%, rgb(255 255 255 / 55%) 0, rgb(255 255 255 / 55%) 0.4px, transparent 1px),
     radial-gradient(circle at 82% 68%, rgb(255 255 255 / 60%) 0, rgb(255 255 255 / 60%) 0.45px, transparent 1px),
     radial-gradient(circle at 35% 78%, rgb(255 255 255 / 45%) 0, rgb(255 255 255 / 45%) 0.35px, transparent 1px),
     radial-gradient(ellipse 70% 50% at 20% 0%, rgb(99 102 241 / 12%), transparent 55%),
     radial-gradient(ellipse 60% 45% at 90% 100%, rgb(34 211 238 / 8%), transparent 50%),
-    linear-gradient(180deg, #050505 0%, #000 55%, #030303 100%) !important;
+    linear-gradient(180deg, #050505 0%, #000 55%, #030303 100%);
   background-size: 100% 100% !important;
   background-repeat: no-repeat !important;
   box-shadow:
@@ -1082,6 +1084,12 @@ html[data-route-scope='drive'] body {
     letter-spacing 0.35s ease;
 }
 
+.ultimail-login button.ultimail-login-connect-btn:disabled {
+  cursor: not-allowed;
+  filter: brightness(0.78);
+  opacity: 1;
+}
+
 .ultimail-login a.ultimail-login-connect-btn > *,
 .ultimail-login button.ultimail-login-connect-btn > * {
   position: relative;
@@ -1126,15 +1134,16 @@ html[data-route-scope='drive'] body {
 }
 
 .dark .ultimail-login a.ultimail-login-connect-btn,
-.ultimail-login button.ultimail-login-connect-btn {
-  background:
+.dark .ultimail-login button.ultimail-login-connect-btn {
+  background-color: #000;
+  background-image:
     radial-gradient(circle at 15% 25%, rgb(255 255 255 / 75%) 0, rgb(255 255 255 / 75%) 0.45px, transparent 1px),
     radial-gradient(circle at 62% 18%, rgb(255 255 255 / 60%) 0, rgb(255 255 255 / 60%) 0.4px, transparent 1px),
     radial-gradient(circle at 82% 68%, rgb(255 255 255 / 65%) 0, rgb(255 255 255 / 65%) 0.45px, transparent 1px),
     radial-gradient(circle at 35% 78%, rgb(255 255 255 / 50%) 0, rgb(255 255 255 / 50%) 0.35px, transparent 1px),
     radial-gradient(ellipse 70% 50% at 20% 0%, rgb(129 140 248 / 14%), transparent 55%),
     radial-gradient(ellipse 60% 45% at 90% 100%, rgb(34 211 238 / 10%), transparent 50%),
-    linear-gradient(180deg, #000 0%, #000 55%, #020202 100%) !important;
+    linear-gradient(180deg, #000 0%, #000 55%, #020202 100%);
   background-size: 100% 100% !important;
   background-repeat: no-repeat !important;
 }

components/auth/auth-connect-button.tsx

@@ -60,7 +60,7 @@ export function AuthConnectButton(props: AuthConnectButtonProps) {
 
   return (
     <div className="ultimail-login-connect-action">
-      <div className="ultimail-login-connect-border">{control}</div>
+      <div className="ultimail-login-connect-border w-full">{control}</div>
     </div>
   )
 }

components/auth/auth-flow-page.tsx

@@ -147,6 +147,7 @@ export function AuthFlowPage({
           component={component}
           submitting={submitting}
           fieldErrors={validationErrors}
+          flowSlug={slug}
           onSubmit={handleSubmit}
         />
       )}

components/auth/flow-challenge-form.tsx

@@ -3,6 +3,13 @@
 import { useEffect, useMemo, useRef, useState } from "react"
 import { Loader2 } from "lucide-react"
 import { AuthConnectButton } from "@/components/auth/auth-connect-button"
+import { PasswordFieldBlock } from "@/components/auth/password-field-block"
+import {
+  isSignupCredentialsStep,
+  SignupCredentialsFields,
+} from "@/components/auth/signup-credentials-fields"
+import { buildSignupEmail } from "@/lib/auth/signup-platform"
+import { AUTH_FLOW_SLUGS } from "@/lib/auth/auth-flow-slugs"
 import { Input } from "@/components/ui/input"
 import { Label } from "@/components/ui/label"
 import type { FlowChallenge } from "@/lib/auth/flow-api"
@@ -22,6 +29,7 @@ type FlowChallengeFormProps = {
   component: string
   submitting: boolean
   fieldErrors?: Record<string, string>
+  flowSlug?: string
   onSubmit: (payload: Record<string, unknown>) => void | Promise<void>
 }
 
@@ -30,13 +38,25 @@ export function FlowChallengeForm({
   component,
   submitting,
   fieldErrors = {},
+  flowSlug,
   onSubmit,
 }: FlowChallengeFormProps) {
   const [values, setValues] = useState<Record<string, string>>({})
+  const [signupCanSubmit, setSignupCanSubmit] = useState(true)
   const initializedComponentRef = useRef<string | null>(null)
 
   const promptFields = useMemo(() => readPromptFields(challenge), [challenge])
   const primaryAction = readPrimaryAction(challenge)
+  const signupCredentials =
+    flowSlug === AUTH_FLOW_SLUGS.enrollment &&
+    component === "ak-stage-prompt" &&
+    isSignupCredentialsStep(promptFields)
+
+  useEffect(() => {
+    if (!signupCredentials) {
+      setSignupCanSubmit(true)
+    }
+  }, [signupCredentials])
 
   useEffect(() => {
     if (initializedComponentRef.current === component) return
@@ -70,7 +90,11 @@ export function FlowChallengeForm({
         const key = field.field_key
         if (field.type === "static") continue
         if (field.type === "hidden") {
-          payload[key] = field.initial_value ?? ""
+          if (key === "email" && signupCredentials) {
+            payload[key] = buildSignupEmail(values.username ?? "")
+          } else {
+            payload[key] = field.initial_value ?? ""
+          }
           continue
         }
         payload[key] = values[key] ?? ""
@@ -96,16 +120,28 @@ export function FlowChallengeForm({
   }
 
   return (
-    <form className="space-y-4" onSubmit={handleSubmit}>
+    <form className="space-y-4" autoComplete="on" onSubmit={handleSubmit}>
       {component === "ak-stage-prompt" ? (
-        <PromptFields
-          fields={promptFields}
-          values={values}
-          fieldErrors={fieldErrors}
-          onChange={(key, value) =>
-            setValues((prev) => ({ ...prev, [key]: value }))
-          }
-        />
+        signupCredentials ? (
+          <SignupCredentialsFields
+            fields={promptFields}
+            values={values}
+            fieldErrors={fieldErrors}
+            onCanSubmitChange={setSignupCanSubmit}
+            onChange={(key, value) =>
+              setValues((prev) => ({ ...prev, [key]: value }))
+            }
+          />
+        ) : (
+          <PromptFields
+            fields={promptFields}
+            values={values}
+            fieldErrors={fieldErrors}
+            onChange={(key, value) =>
+              setValues((prev) => ({ ...prev, [key]: value }))
+            }
+          />
+        )
       ) : null}
 
       {component === "ak-stage-identification" ? (
@@ -154,8 +190,7 @@ export function FlowChallengeForm({
       {isKnownComponent(component) ? (
         <AuthConnectButton
           type="submit"
-          disabled={submitting}
-          className="disabled:opacity-60"
+          disabled={submitting || (signupCredentials && !signupCanSubmit)}
         >
           {submitting ? (
             <>
@@ -232,6 +267,29 @@ function PromptFields({
           )
         }
 
+        if (field.type === "password") {
+          return (
+            <PasswordFieldBlock
+              key={field.field_key}
+              id={field.field_key}
+              label={field.label ?? field.field_key}
+              value={values[field.field_key] ?? ""}
+              error={fieldErrors[field.field_key]}
+              required={field.required}
+              autoComplete={
+                field.field_key.includes("repeat") ? "new-password" : "new-password"
+              }
+              showStrength={field.field_key === "password"}
+              compareWith={
+                field.field_key === "password_repeat"
+                  ? (values.password ?? "")
+                  : undefined
+              }
+              onChange={(value) => onChange(field.field_key, value)}
+            />
+          )
+        }
+
         return (
           <FieldBlock
             key={field.field_key}
@@ -282,15 +340,14 @@ function IdentificationFields({
         required
       />
       {withPassword ? (
-        <FieldBlock
+        <PasswordFieldBlock
           id="password"
           label="Mot de passe"
-          type="password"
-          autoComplete="current-password"
           value={values.password ?? ""}
           error={fieldErrors.password}
-          onChange={(value) => onChange("password", value)}
           required
+          autoComplete="current-password"
+          onChange={(value) => onChange("password", value)}
         />
       ) : null}
     </div>

components/auth/password-field-block.tsx

@@ -0,0 +1,139 @@
+"use client"
+
+import { useState } from "react"
+import { Eye, EyeOff } from "lucide-react"
+import { Input } from "@/components/ui/input"
+import { Label } from "@/components/ui/label"
+import {
+  evaluatePasswordStrength,
+  passwordsMatch,
+  type PasswordStrengthLevel,
+} from "@/lib/auth/password-strength"
+import { cn } from "@/lib/utils"
+
+type PasswordFieldBlockProps = {
+  id: string
+  label: string
+  value: string
+  error?: string
+  required?: boolean
+  autoComplete: "new-password" | "current-password"
+  onChange: (value: string) => void
+  /** Show strength meter (signup password). */
+  showStrength?: boolean
+  /** Compare with primary password (signup confirmation). */
+  compareWith?: string
+}
+
+const STRENGTH_SEGMENTS: PasswordStrengthLevel[] = [
+  "weak",
+  "fair",
+  "good",
+  "strong",
+]
+
+const STRENGTH_ACTIVE: Record<Exclude<PasswordStrengthLevel, "empty">, string> = {
+  weak: "bg-destructive",
+  fair: "bg-amber-500",
+  good: "bg-emerald-500",
+  strong: "bg-emerald-600",
+}
+
+export function PasswordFieldBlock({
+  id,
+  label,
+  value,
+  error,
+  required,
+  autoComplete,
+  onChange,
+  showStrength = false,
+  compareWith,
+}: PasswordFieldBlockProps) {
+  const [visible, setVisible] = useState(false)
+  const strength = evaluatePasswordStrength(value)
+  const match = compareWith !== undefined ? passwordsMatch(compareWith, value) : null
+
+  const activeSegments =
+    strength.level === "empty"
+      ? 0
+      : strength.level === "weak"
+        ? 1
+        : strength.level === "fair"
+          ? 2
+          : strength.level === "good"
+            ? 3
+            : 4
+
+  return (
+    <div className="space-y-2">
+      <Label htmlFor={id}>{label}</Label>
+      <div className="relative">
+        <Input
+          id={id}
+          type={visible ? "text" : "password"}
+          value={value}
+          required={required}
+          autoComplete={autoComplete}
+          aria-invalid={error ? true : undefined}
+          onChange={(event) => onChange(event.target.value)}
+          className="h-10 rounded-lg pr-10"
+        />
+        <button
+          type="button"
+          className="absolute inset-y-0 right-0 flex w-10 items-center justify-center text-muted-foreground transition-colors hover:text-foreground"
+          aria-label={visible ? "Masquer le mot de passe" : "Afficher le mot de passe"}
+          onClick={() => setVisible((v) => !v)}
+        >
+          {visible ? (
+            <EyeOff className="size-4" aria-hidden />
+          ) : (
+            <Eye className="size-4" aria-hidden />
+          )}
+        </button>
+      </div>
+
+      {showStrength && value ? (
+        <div className="space-y-1.5" aria-live="polite">
+          <div className="flex gap-1">
+            {STRENGTH_SEGMENTS.map((level, index) => (
+              <span
+                key={level}
+                className={cn(
+                  "h-1 flex-1 rounded-full bg-muted transition-colors",
+                  index < activeSegments && strength.level !== "empty"
+                    ? STRENGTH_ACTIVE[strength.level === "empty" ? "weak" : strength.level]
+                    : null
+                )}
+              />
+            ))}
+          </div>
+          <p className="text-xs text-muted-foreground">
+            Robustesse :{" "}
+            <span className="font-medium text-foreground">{strength.label}</span>
+          </p>
+        </div>
+      ) : null}
+
+      {match !== null ? (
+        <p
+          className={cn(
+            "text-xs",
+            match ? "text-emerald-600 dark:text-emerald-400" : "text-destructive"
+          )}
+          role="status"
+        >
+          {match
+            ? "Les mots de passe correspondent."
+            : "Les mots de passe ne correspondent pas."}
+        </p>
+      ) : null}
+
+      {error ? (
+        <p className="text-xs text-destructive" role="alert">
+          {error}
+        </p>
+      ) : null}
+    </div>
+  )
+}

components/auth/signup-credentials-fields.tsx

@@ -0,0 +1,320 @@
+"use client"
+
+import { useEffect, useMemo, useState } from "react"
+import { Loader2 } from "lucide-react"
+import { Input } from "@/components/ui/input"
+import { Label } from "@/components/ui/label"
+import { PasswordFieldBlock } from "@/components/auth/password-field-block"
+import { checkMailAddressAvailability } from "@/lib/auth/check-mail-address"
+import {
+  buildSignupEmail,
+  normalizeSignupLocalPart,
+  SIGNUP_MAIL_DOMAIN,
+} from "@/lib/auth/signup-platform"
+import { useDebouncedValue } from "@/lib/hooks/use-debounced-value"
+import { cn } from "@/lib/utils"
+
+type PromptField = {
+  field_key: string
+  label?: string
+  type?: string
+  required?: boolean
+  placeholder?: string
+}
+
+type SignupCredentialsFieldsProps = {
+  fields: PromptField[]
+  values: Record<string, string>
+  fieldErrors: Record<string, string>
+  onChange: (key: string, value: string) => void
+  onCanSubmitChange?: (canSubmit: boolean) => void
+}
+
+export function isSignupCredentialsStep(fields: PromptField[]): boolean {
+  const keys = new Set(fields.map((field) => field.field_key))
+  return keys.has("username") && keys.has("password") && keys.has("password_repeat")
+}
+
+export function SignupCredentialsFields({
+  fields,
+  values,
+  fieldErrors,
+  onChange,
+  onCanSubmitChange,
+}: SignupCredentialsFieldsProps) {
+  const username = values.username ?? ""
+  const normalizedLocal = useMemo(() => normalizeSignupLocalPart(username), [username])
+  const previewEmail = buildSignupEmail(username)
+  const debouncedLocal = useDebouncedValue(normalizedLocal, 1000)
+
+  const [availability, setAvailability] = useState<
+    "idle" | "checking" | "available" | "taken" | "error"
+  >("idle")
+
+  useEffect(() => {
+    if (debouncedLocal.length < 2) {
+      setAvailability("idle")
+      return
+    }
+
+    let cancelled = false
+    setAvailability("checking")
+
+    void checkMailAddressAvailability(debouncedLocal, SIGNUP_MAIL_DOMAIN)
+      .then((result) => {
+        if (cancelled) return
+        setAvailability(result.available ? "available" : "taken")
+      })
+      .catch(() => {
+        if (cancelled) return
+        setAvailability("error")
+      })
+
+    return () => {
+      cancelled = true
+    }
+  }, [debouncedLocal])
+
+  const canSubmit =
+    normalizedLocal.length >= 2 &&
+    availability !== "taken" &&
+    availability !== "checking"
+
+  useEffect(() => {
+    onCanSubmitChange?.(canSubmit)
+  }, [canSubmit, onCanSubmitChange])
+
+  const otherFields = fields.filter(
+    (field) =>
+      field.type !== "hidden" &&
+      field.type !== "static" &&
+      !["username", "password", "password_repeat", "domain_hint"].includes(
+        field.field_key
+      )
+  )
+
+  return (
+    <div className="space-y-4">
+      <div className="space-y-2">
+        <Label htmlFor="username">Adresse e-mail</Label>
+        <div className="relative flex items-center">
+          <Input
+            id="username"
+            name="username"
+            type="text"
+            inputMode="email"
+            autoComplete="username"
+            spellCheck={false}
+            autoCapitalize="none"
+            autoCorrect="off"
+            placeholder={
+              fields.find((field) => field.field_key === "username")?.placeholder ??
+              "prenom.nom"
+            }
+            value={username}
+            required
+            aria-invalid={
+              fieldErrors.username || availability === "taken" ? true : undefined
+            }
+            onChange={(event) =>
+              onChange("username", normalizeSignupLocalPart(event.target.value))
+            }
+            onKeyDown={(event) => {
+              if (event.key === "@") event.preventDefault()
+            }}
+            onPaste={(event) => {
+              const text = event.clipboardData.getData("text")
+              if (!text.includes("@")) return
+              event.preventDefault()
+              onChange("username", normalizeSignupLocalPart(text))
+            }}
+            className="h-10 rounded-lg pr-[9.5rem]"
+          />
+          <span
+            className="pointer-events-none absolute inset-y-0 right-3 flex items-center text-sm text-muted-foreground"
+            aria-hidden
+          >
+            @{SIGNUP_MAIL_DOMAIN}
+          </span>
+        </div>
+
+        <input
+          type="email"
+          name="email"
+          autoComplete="email"
+          value={previewEmail}
+          readOnly
+          tabIndex={-1}
+          aria-hidden
+          className="sr-only"
+        />
+
+        <p className="text-xs text-muted-foreground">
+          Votre adresse sera{" "}
+          <span className="font-medium text-foreground">
+            {previewEmail || `identifiant@${SIGNUP_MAIL_DOMAIN}`}
+          </span>
+        </p>
+
+        <AvailabilityHint
+          local={normalizedLocal}
+          debouncedLocal={debouncedLocal}
+          status={availability}
+        />
+
+        {fieldErrors.username ? (
+          <p className="text-xs text-destructive" role="alert">
+            {fieldErrors.username}
+          </p>
+        ) : null}
+      </div>
+
+      <PasswordFieldBlock
+        id="password"
+        label="Mot de passe"
+        value={values.password ?? ""}
+        error={fieldErrors.password}
+        required
+        autoComplete="new-password"
+        showStrength
+        onChange={(value) => onChange("password", value)}
+      />
+
+      <PasswordFieldBlock
+        id="password_repeat"
+        label="Confirmer le mot de passe"
+        value={values.password_repeat ?? ""}
+        error={fieldErrors.password_repeat}
+        required
+        autoComplete="new-password"
+        compareWith={values.password ?? ""}
+        onChange={(value) => onChange("password_repeat", value)}
+      />
+
+      {otherFields.map((field) => (
+        <GenericSignupField
+          key={field.field_key}
+          field={field}
+          value={values[field.field_key] ?? ""}
+          error={fieldErrors[field.field_key]}
+          onChange={(value) => onChange(field.field_key, value)}
+        />
+      ))}
+    </div>
+  )
+}
+
+function AvailabilityHint({
+  local,
+  debouncedLocal,
+  status,
+}: {
+  local: string
+  debouncedLocal: string
+  status: "idle" | "checking" | "available" | "taken" | "error"
+}) {
+  if (local.length === 0) return null
+  if (local.length < 2) {
+    return (
+      <p className="text-xs text-muted-foreground">
+        Au moins 2 caractères avant le @.
+      </p>
+    )
+  }
+
+  if (local !== debouncedLocal || status === "checking") {
+    return (
+      <p className="flex items-center gap-1.5 text-xs text-muted-foreground">
+        <Loader2 className="size-3 animate-spin" aria-hidden />
+        Vérification de la disponibilité…
+      </p>
+    )
+  }
+
+  if (status === "available") {
+    return (
+      <p className="text-xs text-emerald-600 dark:text-emerald-400" role="status">
+        Cette adresse est disponible.
+      </p>
+    )
+  }
+
+  if (status === "taken") {
+    return (
+      <p className="text-xs text-destructive" role="alert">
+        Cette adresse est déjà prise.
+      </p>
+    )
+  }
+
+  if (status === "error") {
+    return (
+      <p className="text-xs text-muted-foreground">
+        Impossible de vérifier la disponibilité pour le moment.
+      </p>
+    )
+  }
+
+  return null
+}
+
+function GenericSignupField({
+  field,
+  value,
+  error,
+  onChange,
+}: {
+  field: PromptField
+  value: string
+  error?: string
+  onChange: (value: string) => void
+}) {
+  if (field.type === "file") {
+    return (
+      <div className="space-y-2">
+        <Label htmlFor={field.field_key}>{field.label}</Label>
+        <Input
+          id={field.field_key}
+          type="file"
+          accept="image/*"
+          onChange={(event) => {
+            const file = event.target.files?.[0]
+            if (!file) {
+              onChange("")
+              return
+            }
+            const reader = new FileReader()
+            reader.onload = () => onChange(String(reader.result ?? ""))
+            reader.readAsDataURL(file)
+          }}
+        />
+      </div>
+    )
+  }
+
+  return (
+    <div className="space-y-2">
+      <Label htmlFor={field.field_key}>{field.label}</Label>
+      <Input
+        id={field.field_key}
+        type="text"
+        value={value}
+        required={field.required}
+        autoComplete={autoCompleteForField(field.field_key)}
+        onChange={(event) => onChange(event.target.value)}
+        className="h-10 rounded-lg"
+      />
+      {error ? (
+        <p className="text-xs text-destructive" role="alert">
+          {error}
+        </p>
+      ) : null}
+    </div>
+  )
+}
+
+function autoCompleteForField(fieldKey: string): string | undefined {
+  if (fieldKey === "name") return "name"
+  if (fieldKey.includes("phone")) return "tel"
+  return undefined
+}

lib/auth/check-mail-address.ts

@@ -0,0 +1,22 @@
+export type MailAddressAvailability = {
+  available: boolean
+  reason?: string
+}
+
+export async function checkMailAddressAvailability(
+  local: string,
+  domain: string
+): Promise<MailAddressAvailability> {
+  const params = new URLSearchParams({
+    local,
+    domain,
+  })
+  const res = await fetch(`/api/v1/mail/addresses/check?${params.toString()}`, {
+    credentials: "include",
+    headers: { Accept: "application/json" },
+  })
+  if (!res.ok) {
+    throw new Error(`address check failed (${res.status})`)
+  }
+  return (await res.json()) as MailAddressAvailability
+}

lib/auth/password-strength.ts

@@ -0,0 +1,37 @@
+export type PasswordStrengthLevel = "empty" | "weak" | "fair" | "good" | "strong"
+
+export type PasswordStrength = {
+  level: PasswordStrengthLevel
+  score: number
+  label: string
+}
+
+export function evaluatePasswordStrength(password: string): PasswordStrength {
+  if (!password) {
+    return { level: "empty", score: 0, label: "" }
+  }
+
+  let score = 0
+  if (password.length >= 8) score += 1
+  if (password.length >= 12) score += 1
+  if (/[a-z]/.test(password) && /[A-Z]/.test(password)) score += 1
+  if (/\d/.test(password)) score += 1
+  if (/[^A-Za-z0-9]/.test(password)) score += 1
+
+  if (score <= 1) {
+    return { level: "weak", score, label: "Faible" }
+  }
+  if (score === 2) {
+    return { level: "fair", score, label: "Moyen" }
+  }
+  if (score === 3 || score === 4) {
+    return { level: "good", score, label: "Bon" }
+  }
+  return { level: "strong", score, label: "Fort" }
+}
+
+export function passwordsMatch(a: string, b: string): boolean | null {
+  if (!a && !b) return null
+  if (!b) return null
+  return a === b
+}

lib/auth/signup-platform.ts

@@ -0,0 +1,11 @@
+/** Platform mail domain for self-service signup (Authentik enrollment). */
+export const SIGNUP_MAIL_DOMAIN = "ultisuite.fr"
+
+export function normalizeSignupLocalPart(raw: string): string {
+  return raw.replace(/@+/g, "").trim().toLowerCase()
+}
+
+export function buildSignupEmail(local: string): string {
+  const normalized = normalizeSignupLocalPart(local)
+  return normalized ? `${normalized}@${SIGNUP_MAIL_DOMAIN}` : ""
+}