Mobile settings and account per the workspace settings contract #30

Part of #14 (W3 — mobile v1). Blocked by the shell + auth slices.

Outcome

The account/settings surface matches the workspace settings contract: account-wide settings and OAuth-app-scoped /config stay on their owning boundaries.

Scope

• Username/email account identity and sign out (#62)
• Avatar and disk-usage storage bar (design-system storage-bar; feat(settings): show account storage #80) — merged
• Account-wide settings via SDK (feat(settings): add account settings state layer #77 → feat(settings): add mobile account controls #78): default sort order (feat(settings): add the default sort order picker #138), tunnel route "Choose your proxy" picker (feat(settings): add the proxy route picker #137), use_start_from (feat(settings): add the resume playback switch #136), subtitle settings, history_enabled, and trash_enabled with confirm-if-emptying are all merged
• OAuth-app-scoped /config, owned and parsed by Android: playback type (HLS/MP4), buffer size, autoplay next. Launch appearance is dark-only and exposes no theme override — feat(settings): add Android app config core #104/feat(settings): add mobile app playback preferences #105 (buffer size intentionally excluded: no authoritative server key); runtime consumption in feat(playback): honor configured video format #109/feat(playback): autoplay the next video #110
• Privacy controls: strictly-necessary disclosure plus separate diagnostics_enabled, product_analytics_enabled, and support_widget_enabled rows per putdotio/support#95 (feat(settings): add privacy controls with a strictly necessary disclosure #141; server round trip proven against putdotio/putio#4688)
• Trash management entry (feat(account): browse Trash and restore individual items #130) and About/app info with support-safe fields and copy-for-support (feat(settings): add the About section with support-safe app info #140); a diagnostics entry point (connection/playback tests) stays gated behind diagnostics_enabled, putdotio/putio#4687
• Rows modeled per settings-contract IA (icon + title + description + state + accessory): audited against the full tree on 56aa1eb; every row has a Phosphor icon, title, description, and either a switch, a value accessory (sort, proxy, playback, version), or the always-on disclosure

Acceptance criteria

• Account-wide settings and Android-owned app config each round-trip against their API boundary: raw GET /account/settings matches every account row (subtitles, history, trash, resume, proxy cdn77, sort NAME_ASC, three privacy keys) and the Diagnostics write round-tripped false/true; Autoplay on /config survived a cold restart (https://attach.uinaf.dev/p/mwolQ4gncdydwVnexpqW7g)
• Optional diagnostics, analytics, and support tooling remains disabled when its corresponding control is off: no vendor SDK is integrated yet, so nothing runs regardless; the three switches are the kill switches Mobile v1 release: one-package Play identity, Actions release lane, and Sentry #31 must honour when Sentry lands
• DoD: verify green on 56aa1eb; full settings tree: https://attach.uinaf.dev/p/6hkjL2xjx5ziIb8pkT4fOg · https://attach.uinaf.dev/p/A5IQ4Er071oV3ghnCC-8Xg · https://attach.uinaf.dev/p/nAZso65jpgeoxZee6blQnA · https://attach.uinaf.dev/p/3io31cNtbQ4PeooS394AjQ