feat(auth): typed PasswordResetException sealed class

app/src/main/java/app/closer/domain/repository/PasswordResetException.kt

@@ -0,0 +1,18 @@
+package app.closer.domain.repository
+
+/**
+ * Typed reasons a "forgot password" request can't complete, mapped from Firebase specifics at the auth
+ * data-source boundary. Using these instead of matching on Firebase's human-readable error strings keeps
+ * detection robust across SDK/locale changes; the UI layer owns the user-facing copy per type.
+ *
+ * Note: under Firebase email-enumeration protection (enabled on this project), a reset for an unknown or
+ * Google-only address returns success — so [NoAccount] is only surfaced if that protection is disabled.
+ * The Google-only case is handled by enumeration-safe copy in the UI rather than a provider lookup.
+ */
+sealed class PasswordResetException(message: String) : Exception(message) {
+    /** No account exists for the given email (only reachable when email-enumeration protection is off). */
+    class NoAccount : PasswordResetException("No account for email")
+
+    /** The email address is malformed (a pure format check; always applies). */
+    class InvalidEmail : PasswordResetException("Malformed email")
+}