chore(sync): merge upstream/main 6524a8d437 into custom-v2, plus a repeatable sync routine

[ziyadakl]

Summary

Brings the official T3 Code into custom-v2: 581 upstream commits, up to 6524a8d437 (2026-10-13). It also adds a routine so later syncs take one command.

custom-v2 (25d33ffcc8) ─┐
                        ├─ merge 004d7752d2 ── routine 391b96ac54 ── review fixes 2c8f1a2e61..add112d5e5
upstream/main (6524a8d) ┘

+CUSTOM.md                          # every fork feature, its files, and when to drop it for upstream's
+scripts/custom/sync-upstream.sh    # start: merge upstream into a sync branch (rerere on, replayed fixes listed for review)
+                                   # check: no unfinished merge or conflict markers, then the same checks as ci.yml

The merge had 40 conflicted files. Upstream wins each one, except where a feature in CUSTOM.md needs our side.

• Dropped: our test PID fix e4807aa77f. Upstream fixed the same test in 202b95403a.
• Kept working: rewinding to a Claude turn stopped before its prompt echo. Upstream f570bd2166 made prompt ids random, so new turns now record the id they send. Turns from older builds fall back to the old derived id.
• Changed: trusted-device pairing adopts upstream's rule for partial permissions.
• Upstream now covering ours: no custom feature.

Review fixes (four-axis review):

• Upstream's new ProjectSettingsPanel test mocks our archive hook; Test Web was red.
• agentSessionsResume is in CLIENT_GUARDED_RPC_SCOPES.
• The mobile Home screen shares the unarchived-projects hook.
• The sync script no longer auto-stages replayed fixes. Its record keeps 365 days, it refuses a same-day rerun, it names a missing upstream remote, and check mirrors ci.yml.
• Rewinding while Claude runs took about 9 s. 8.25 s of that was a fresh Claude process, opened only to check files, waiting on a project SessionStart hook (7.5 s). Restore-only processes now pass settingSources: []. Measured: 8.2 s -> 0.6 s, with the same rewindFiles answers (9c1ee8f).

Evidence

• Before: custom-v2 is 581 commits behind upstream. The running build lacks upstream's reconnect fixes: fix(server): shell snapshots no longer block other database reads while decoding pingdotgg/t3code#17141, perf(mobile): reuse encoded rows in shell cache saves pingdotgg/t3code#16129, fix(mobile): attachment images no longer re-download on every reconnect pingdotgg/t3code#18824 and perf(server): drive shell last-error lookup from thread bindings pingdotgg/t3code#17842.
  After: the branch contains both upstream/main and origin/custom-v2.
• Rewind: the new test can rewind to a turn stopped before Claude echoed its prompt failed with "no SDK assistant message cursor was recorded".
  After: the full ClaudeAdapterV2.test.ts passes, 263/263.
• Test Web: ProjectSettingsPanel.test.tsx failed 10/10 on a missing mock export.
  After: 10/10 pass.
• Repo-wide: typecheck exit 0. Lint shows 0 errors. fmt:check and knip:check pass.
• Sync script: tested in a throwaway clone for five cases:
  • missing remote: exit 1;
  • clean merge: exit 0;
  • same-day rerun: exit 1;
  • conflict: exit 2;
  • a redone sync lists replayed fixes for review.
• Not tested live: a real Claude rewind, phone pairing, and the mobile Home screen (typecheck only).

Merge Danger

Door: one-way, once installed

Merging alone builds a new 0.0.45-custom.<sha> and installs nothing. Installing it runs upstream's database migrations 059–061. After that, switching back to 0.0.45-custom.ae0c0557 means an older build on a newer schema, which is not guaranteed to work. Copy ~/.t3/userdata/statev2.sqlite on each machine before installing.

Blast Radius: everywhere

Once installed, every machine runs it: the Mac and all three Work boxes. Rewind and trusted-device pairing changed the most. Test those first.

🤖 Generated with Claude Code