T3 Code Fork 0.1.401

What's Changed

• sync: upstream 18e2742..8c0670b (159 commits) by @Bl4ckBl1zZ in #419
• sync: upstream 8c0670b..1316d48 (248 commits) by @Bl4ckBl1zZ in #420
• sync: upstream 1316d48..cc0b86d (7 commits) by @Bl4ckBl1zZ in #421
• feat(server): deleting a thread cleans up its worktree, branch, scratch folder, and checkpoints by @Bl4ckBl1zZ in #422
• fix(server): label T3 Code's Claude requests as t3-code by @Bl4ckBl1zZ in #423
• sync: upstream cc0b86d..6bbb2d8 (108 commits) by @Bl4ckBl1zZ in #424

Full Changelog: fork-v0.1.400...fork-v0.1.401