What Changed

Cherry-picked 7 upstream commits from pingdotgg/t3code into the fork, integrating:

• Selective file staging in commit dialog (feat: add selective file staging to commit dialog pingdotgg/t3code#872)
• Editor preferences refactor and useLocalStorage helper (fix(web): resolve preferred editor from available editors & introduce useLocalStorage helper pingdotgg/t3code#662)
• Prompt editor business logic and cursor bug fixes (fix: improve business logic in prompt editor and fix cursor bugs in Plan mode pingdotgg/t3code#867)
• Response duration tracking fix (fix: Fix response duration for agent to no longer always be 1ms pingdotgg/t3code#866)
• Diff panel unclosable fix (fix: diff panel unclosable after retainSearchParams middleware pingdotgg/t3code#937)
• Logo alignment regression fix (fix: fix logo aligment regression on macOS pingdotgg/t3code#960)
• Contributor update (add Ymit24 to vouched list pingdotgg/t3code#959)

All commits integrated cleanly with one conflict resolved in ChatView.logic.ts (merged both fork's CodexReasoningEffort and upstream's ProjectId imports).

Why

Syncs the fork with important upstream fixes and improvements while preserving fork-specific customizations (Agent SDK integration, worktree branch sync, PR review button, ChatView component split).

Testing

• TypeScript compilation: ✅ zero errors (apps/server and apps/web)
• Unit tests: ✅ MessagesTimeline.logic.test.ts (7/7), appSettings.test.ts (5/5)
• Integration tests: pre-existing timeouts in GitCore (unrelated to cherry-picks)