Land W0–W7 design for the Flutter web preview surface with
acceptance criteria, Master actions, and N4-W tracking. Cross-link
README, roadmap, deploy-checklist, fcm-setup, and mobile README.
Q9 remains out of scope; implementation waits per-Wi approval.
Co-authored-by: okuma <o0kuma@users.noreply.github.com>
Prefer FCM_SERVICE_ACCOUNT_FILE/JSON over legacy FCM_SERVER_KEY,
mount secrets/ into core-backend, and document Master JSON placement.
Co-authored-by: okuma <o0kuma@users.noreply.github.com>
Add PushTokenService with Firebase Messaging fallback to install
placeholders, conditional google-services Gradle plugin, fcm-setup.md,
and mark Android UI checklist api-done via prod e2e 16/16.
Co-authored-by: okuma <o0kuma@users.noreply.github.com>