Chromecast support in the mobile app (VPN/tunnel-safe) #36

Part of #14 (W3, mobile v1). In v1 since the 2026-08-08 decision: iOS v1 ships Chromecast, and Cast matters more on Android than AirPlay does on iOS. Unblocked: #27 and putdotio/putio-sdk-kotlin#30 are closed.

Outcome

Cast video and audio from the mobile app to a Cast device, with playback that works over the user's tunnel or proxy route (design brief §I: casting must work under VPN).

Scope

• Cast SDK integration, route-aware stream URLs that work with the tunnel or proxy, cast controls and notification, and resume consistent with start-from.
• Decide HLS vs MP4 on Cast receivers. Android owns the app-specific key and its parsing through the OAuth-app-scoped /config boundary from fix(config): expose app-scoped values generically putio-sdk-kotlin#30, and shows it in mobile settings (built in Mobile settings and account per the workspace settings contract #30). Define subtitle delivery on Cast.

Cast SDK analytics

The Android Cast SDK's analytics can't be turned off. CastOptions.Builder has no analytics toggle, and Google's Cast SDK data disclosure says neither the developer nor the user can opt out. iOS turns it off with disableAnalyticsLogging = true (putio-ios@273c450a on next, putio-ios@ea7e3126 on main); Android has no equivalent.

So on Android, Cast analytics can't follow the product-analytics opt-in (putdotio/support#95). Treat it as part of the casting feature, not product analytics:

• Google Cast is listed on the Services page (/services-we-use, putdotio/putio-web#1236) as part of casting, including the analytics Google collects, before this ships.
• The Play Data Safety form (Mobile v1 release: one-package Play identity, Actions release lane, and Sentry #31) declares Cast SDK collection per the disclosure above.

Acceptance criteria

• Verify green; a recording of a phone-to-Cast session (start, seek, subtitles, disconnect) is attached.
• Both Cast SDK analytics items above are done.

Written by an agent (Claude Code, Claude Opus 5.5)