build(release): Android signing, iOS privacy manifest, store assets (Phase 7)

- Android: release keystore signing wired via gitignored key.properties (falls
  back to debug when absent). Verified: signed AAB built (signer CN=Block Seasons).
- iOS: app PrivacyInfo.xcprivacy (ATT tracking flag, device-id/usage data types,
  UserDefaults+FileTimestamp required-reason APIs) registered in the Runner target.
- Store: app-ads.txt (pub-5605900229781491), EN/KO listing copy, owner submission
  guide (privacy labels, app-ads hosting, upload/submit steps).
Secrets (keystore, key.properties) are gitignored — owner backs them up.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.gitignore

@@ -53,3 +53,11 @@ CLAUDE.md
 # Firebase Hosting (CLI deploy cache + generated content payload)
 .firebase/
 /deploy/content/
+
+# Android release signing — NEVER commit (owner backs these up out-of-band)
+android/key.properties
+*.jks
+*.keystore
+
+# Kotlin/Gradle build caches
+android/.kotlin/