Update STUDIO.md to CLI site start

[sejas]

Related issues

• Related to the AI instructions feature flag removal effort

How AI was used in this PR

Claude Code assisted with identifying where updateManagedInstructionFiles was called and generating the code changes. All changes were reviewed manually.

Proposed Changes

• Move updateManagedInstructionFiles from Electron main process (ipc-handlers.ts) to CLI site start command (start.ts), so CLI-managed sites also get updated STUDIO.md on every start
• Remove CLAUDE.md from managed instruction files — only STUDIO.md is now auto-updated on site start (CLAUDE.md is user-editable)
• Update tests to reflect the narrower managed files list

Testing Instructions

• Build the CLI: npm run cli:build
• Create a site: node apps/cli/dist/cli/main.js site create --path /tmp/test-site
• Verify STUDIO.md exists in the site root
• Modify STUDIO.md content manually
• Stop and restart the site: node apps/cli/dist/cli/main.js site start --path /tmp/test-site
• Modify manually STUDIO.md, keep the file but update its content.
• Verify STUDIO.md was restored to the bundled version

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?

[wpmobilebot]

📊 Performance Test Results

Comparing a0702e5 vs trunk

app-size

Metric	trunk	a0702e5	Diff	Change
App Size (Mac)	1246.65 MB	1246.65 MB	0.00 MB	⚪ 0.0%

site-editor

Metric	trunk	a0702e5	Diff	Change
load	1943 ms	1928 ms	15 ms	⚪ 0.0%

site-startup

Metric	trunk	a0702e5	Diff	Change
siteCreation	8170 ms	8177 ms	+7 ms	⚪ 0.0%
siteStartup	4815 ms	4143 ms	672 ms	🟢 -14.0%

---

Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change (<50ms diff)

[fredrikekelund]

Works as expected 👍