[adampeterhiggins]

What’s in this sync

Adds 431 upstream commits since the parent sync.

• New features: UI language settings and translations for Spanish, Chinese, French, German, Japanese, Korean, Russian and Brazilian Portuguese; mobile language selection; reply from assistant hover actions; resolved review conversations fold into avatars; quoted messages display as inset cards; Windows background service support. Add-project lists default to GitHub until other hosts are enabled.
• Fixes: more reliable Stop and delegation completion, scheduled-task missed-slot reporting, worktree creation and cleanup with large output, composer chip restoration, streaming scroll behavior, mobile settings and review navigation, and desktop update recovery.
• Provider and internal changes: Cursor streaming and steering improvements, Claude delegate process cleanup and custom model handling, Codex policy errors and delegate lifecycle fixes, OpenCode service restart on update, and lower-cost thread/state processing.

Discord announcements were not used: the channel returned no matching announcement crossposts for this range.

Parent #572 has merged. This PR now targets main and adds only the newer upstream commits.

Base: ae9bd790f5f277097dd72f3998c4825829a40852.
Pinned upstream: ee90bdc9405d8d4b8ff78ce2133ccb04844298ab.
Range: ae9bd790f5f277097dd72f3998c4825829a40852..ee90bdc9405d8d4b8ff78ce2133ccb04844298ab.

Other notable changes: Windows service support (pingdotgg#34524), provider health checks (pingdotgg#34885), large worktree Git output (pingdotgg#34889), Codex child cleanup (pingdotgg#34829), missed scheduled runs (pingdotgg#34815), desktop update recovery (pingdotgg#34932), and singular CSV/text preview labels (pingdotgg#34992).

Full upstream comparison.

Conflict resolutions and verification

• Preserved fork context integrations, provider/account selection, quick-message and split-view behavior, citation comments/chips, notification rules, scheduling catch-up, and worktree naming before setup while adopting upstream structure and guards.
• Unified worktree launch errors and receipt replay checks; retained bounded branch naming and background rename; incorporated upstream failure notices and root-branch capture.
• Integrated Cursor asynchronous steering acknowledgments and patched SDK alongside fork provider environments. Preserved desktop fork publishing/staging tests and upstream Linux window class coverage.
• Repaired clean-merge test imports, new service dependencies and replay signatures. Removed dead citation/skill helpers and reconciled fork documentation where upstream adopted behavior.
• No substantial upstream split of the fork-edited chat/composer files occurred in this range; reviewed caller wiring for preserved composer, citation, detached-window, sidebar, and account features.

Focused validation: web/mobile/client-runtime/contracts/shared/provider typechecks; server typecheck; 503 web unit tests; 939 initial server tests plus 720 cases in the final affected suites (overlapping); 92 launch cases; 155 package cases, 61 thread-sync cases and 11 Cursor replay cases; 62 desktop build cases. Formatting/lint/knip passed. check:changed: format, lint, knip, generated GraphQL, dependency patch validation, 41 affected-package/dependent typechecks and node tests passed.

The 547-file non-browser suite then ran in 28 batches, and 18 passed. Each failure was rerun alone and compared with origin/main and with the pinned upstream commit.

Merge regressions, fixed

• dff33000b0: quoted mixed selections keep their code fence, and the response context preview is registered in kind order. These are fork tests on main.
• cee1db2c56: the merge dropped upstream's linkedSender on cross-environment sends (PeerForwarding and "records the linked environment's thread"). The fork's catch-up path also skipped upstream's failed status for a missed fixed-time slot (fix(server): a missed fixed-time slot shows as failed on its scheduled task pingdotgg/t3code#34815). The agent-context budget now matches the merged instructions; the growth comes from upstream's prompt edits. The schedule test now mocks the dispatch that the fork's service calls. Every scheduled-task, catch-up, peer and budget test file passes (135 tests).

Open: needs a decision or a fix before merge

• SelectionRestart "a workspace handoff during a run does not leave the run interrupted" (fix(server): successful worktree handoffs complete normally pingdotgg/t3code#24545). Upstream now completes a run when a handoff moves its worktree. The fork's orchestrator still settles that run as interrupted and adds the documented Workspace changed divider (WorkspaceChangeDetach.integration.test.ts, docs/fork-differences.md). Pick one behavior and update the other test.
• OrchestratorMcpService "a blocking remote delegation cancelled mid-wait wakes its parent" (fix(server): a steer during a delegate_task wait no longer drops the child's result pingdotgg/t3code#27387). The local variant passes. The remote variant times out at 120s even though upstream's lines and remoteTarget are present, so the fork's remote wait path needs debugging.
• ServerBrowser "a queued recording stop still runs after its deadline". This fork test passes on main and now fails with "The recording captured no frames." The likely cause is upstream's recording change (fix(server): keep the last page state in agent recordings pingdotgg/t3code#33931).

Fails on macOS on upstream's code too; not caused by the merge

• pinnedRuntime symlinked home and ManagedProjectFolders symlinked Scratch. The code is identical to upstream; the temp directory is under /var, which is itself a symlink on macOS.
• ClaudeSkills synced namespace. The fixture creates both pstack and PSTACK, which collide on a case-insensitive disk.

Flaky under load: DeviceHubProxy stream close timed out only in the batch run and passes alone. The disk was 98–99% full during the batches.

Runtime: the web client pairs and opens a thread and Settings → General. The iOS dev client installs and Metro serves it, but the Expo dev menu blocked confirming pairing, so mobile is unverified. Android is unavailable on this machine (no Android SDK). The MCP eval is blocked by a missing API key. Discord returned no matching announcements.

Merge with Create a merge commit. It keeps upstream history and the merge base for the next sync.

Model: gpt-6.1-sol, grok-4.7, then claude-opus-5-5. Harness: Codex and Cursor in T3 Code.