Client Profile: save-phone banner for anonymous users

Anonymous customers now see a brand-gradient "Simpan Nomor HP" panel
above the user card on the kamu tab, ported from the Figma SProfile
save-phone banner. Tapping it pushes /auth/register?from=profile, which
hides the "lanjut tanpa verifikasi (harga normal)" link — a user who
re-entered the verif funnel from Profile shouldn't be re-offered the
anon exit. Spec §1.3 added documenting the ?from= entry-point
convention.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

requirement/phase4-customer-flow.md

@@ -85,6 +85,17 @@ this doc.
 ### 1.2 Backend
 - New: `GET /api/client/onboarding-state` → returns `{ has_paid_first_session: bool }`. Used by client_app to pick whether to show this sheet.
 
+### 1.3 Profile re-prompt for anon users (shipped 2026-05-22)
+
+> Figma: `screens/extras.jsx::SProfile` save-phone banner (lines 170-204).
+> Code: `client_app/lib/features/profile/profile_screen.dart::_SavePhoneBanner`.
+
+For users who chose the anon path in §1 and later open the **kamu** (Profile) tab, a brand-gradient banner appears between the page title and the user card. Body copy: *"Biar riwayat curhat kamu tersimpan, yuk simpan Nomor Handphone kamu…"*. CTA `Simpan Nomor HP` pushes `/auth/register?from=profile`.
+
+- Banner gates on `authData is AuthAnonymousData` — disappears the moment the auth state flips to `AuthAuthenticatedData` after a successful OTP verify.
+- The `?from=profile` query param causes `RegisterScreen` to **omit** the *"lanjut tanpa verifikasi (harga normal)"* escape-hatch link. A user who tapped the banner deliberately re-entered the verif funnel, so we don't re-offer the anon exit.
+- Convention for future entry points: when pushing into `/auth/register` from somewhere that should branch the screen (copy, escape hatch, post-OTP destination), pass `?from=<callsite-slug>` and read `GoRouterState.of(context).uri.queryParameters['from']` in `RegisterScreen.build()`. The router's redirect preserves query params for anonymous users on `/auth/*` routes.
+
 ## 2. ESP screening + USP screen
 
 > Figma: `screens/onboarding.jsx::S5ESP` and `S5USP`. Existing