chore: sync upstream/main into fork

[adampeterhiggins]

The fork was 8 commits behind upstream/main and 260 commits ahead. Merge upstream through cd41c4a, bringing settle actions, faster GitHub/status refreshes, tool-image storage cleanup, refreshed project skills, and Claude compact-on-send behavior while retaining fork features.

Conflict resolutions:

• Server: keep Conductor setup fallback and file copying on setup; settle actions use upstream selection without preparing the existing worktree. Add a regression test and update completion fixtures to emit the returned shell prompt.
• Web/desktop: retain Conductor Run/Stop actions and the known-model context window fallback; keep settle-only actions reachable in the menu and adopt upstream compaction behavior.
• Mobile: retain Conductor actions and use the shared project-action label, including settle actions.
• Fix the existing workspace-handoff test fixture's nullable cwd fallback. Reviewed fork differences; no described fork behavior was removed or adopted upstream in this sync.

Validation:

• Contracts, server, web, and mobile typechecks passed.
• Focused tests: 527 passed in the initial 12-file run; after updating the two completion fixtures, all 13 setup-runner tests passed. Workspace-handoff integration test also passed.
• One existing Git diff test still fails because mode-only.sh is absent from the diff metadata. Reproduced the identical failure with the pre-sync origin/main GitVcsDriverCore implementation.
• Targeted formatting/lint passed (0 errors, 92 warnings); git diff --check passed. Used the repository-local Vite+ runner after detecting a global-runner version mismatch.
• No browser verification or screenshots were taken; browser use was not requested.

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

Model: gpt-6.1-sol (medium reasoning). Harness: Codex in T3 Code.