Make Android consumption-only for subscriptions and credits

[AnthonyRonning]

Android currently opens Stripe and Bitcoin checkout from pricing, credits and subscription management. Make the Android app consumption-only in response to the Play Payments policy notice, while preserving existing subscriptions, credit consumption, API access, team membership and redemption of already-owned passes.

Android pricing now shows plan information without mounting legacy checkout effects, including selected_plan callbacks. Purchase and portal API helpers reject Android calls before making requests. Remove purchase buttons, web promotions and marketing-site exits on Android; keep legal pages in the app and email support available. Web, desktop and iOS retain their existing purchase paths. No billing-server, database, SDK or entitlement changes.

Google explicitly permits consumption-only paid services and purchase communication outside the app: https://support.google.com/googleplay/android-developer/answer/10281818

Validation

• Pinned Nix frontend formatting, ESLint, TypeScript and all 1,263 tests pass (13 existing ESLint warnings, no errors); pre-commit checks also pass.
• New/extended tests cover Android payment requests being blocked before fetch/open, old pricing callbacks remaining unmounted, subscription management using support rather than portals, read-only credit balances, pass access and legal/navigation links. Non-Android behavior remains covered.
• PR-profile web build passes, using the repository's hosted Dev build profile. This is compilation evidence; no live account or billing integration was exercised.
• Independent source review completed; preserved pass navigation and corrected team-seat messaging based on findings.
• Android APK/AAB build and device/emulator smoke have not run on this macOS host (repository Android toolchain targets x86_64 Linux, and no Android SDK/emulator is installed). Existing PR change detection skips native packaging for frontend-only edits.

Rollout

This PR does not clear the Play warning by itself. After review/merge, build a new Android release, smoke the purchase-free flows on Android, and submit it through Play Console before the notice's October 21 deadline. No store upload, release or live configuration change is included here.

[github-actions]

Maple development preview: https://923ecc59.maple-ca8.pages.dev

Commit: 7973b8037b2e124963e0aa2fc438516bb23d3c61

Uses development API, billing, flags and PCR configuration. Cloudflare Access applies.