fix(dev): one t3.json setup action that works on every OS

[t3dotgg]

Worktree setup broke on every Mac and Linux machine I have. t3.json has two setup actions, one for macOS/Linux and one for Windows, and both are marked to run on worktree create. Only one setup action can be active. Importing an action from Settings saves it to every environment. So importing "Setup Worktree (Windows)" once made it the setup action on six machines. Then zsh and bash failed on New-Item with exit 127.

The fix: t3.json now has one "Setup Worktree" action, node scripts/setup-worktree.ts. The script uses only Node built-ins, because it runs before dependencies exist. It runs vp i, links the main checkout's .env files into the worktree, and warms the web dependency cache. The command has no shell syntax, so it works the same in zsh, bash, fish, and PowerShell. It also works when one import is saved to environments on different OSes.

Small changes from the old commands:

• A missing source .env is skipped, so the script makes no broken link.
• When the script runs in the main checkout itself, it does not relink, so it cannot replace the real .env.

This is a smaller version of the idea in #6268.

Proof: I ran the script in this worktree under zsh and bash. Results: deps installed, cache warmed, and .env linked to the main checkout. A missing infra/relay/.env was skipped. When root equals the worktree, an existing .env was left as is. With no vp on PATH, it exits 127. With no T3CODE_PROJECT_ROOT, it stops with a clear error. tsc for scripts/ passes, and lint and format checks are clean.

Created with Claude Opus 5.5 in Claude Code.

🤖 Generated with Claude Code

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This is a focused development-workflow refactor that consolidates OS-specific worktree setup without changing product runtime behavior. The new bootstrap file also adds a static-analysis diagnostic suppression, so human review is warranted.

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[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.5 KiB	13.5 KiB	+10 B (+0.1%)	15.1 KiB	✅
Codex	Thread snapshot wire	7.1 KiB	7.1 KiB	−3 B (−0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.4 KiB	6.5 KiB	+13 B (+0.2%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	56.2 KiB	56.3 KiB	+44 B (+0.1%)	66.4 KiB	✅
Codex	Live turn messages	9	10	+1 (+11.1%)	21	✅
Claude	Total thread wire	13.5 KiB	13.5 KiB	+11 B (+0.1%)	15.1 KiB	✅
Claude	Thread snapshot wire	7.1 KiB	7.1 KiB	+7 B (+0.1%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.4 KiB	6.5 KiB	+4 B (+0.1%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	57.0 KiB	57.0 KiB	0 B (0.0%)	66.4 KiB	✅
Claude	Live turn messages	9	9	0 (0.0%)	21	✅

Baseline: d10bd13 · PR result: 066a9de · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 114.0 KiB
• Claude decoded thread snapshot: 114.7 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.