This commit fixes two critical bugs in the galaxy navigation:
**Bug #1: Direct node URLs redirected to /chat**
- Updated AppStateMachine to recognize /galaxy/* paths (including query params) as galaxy state
- Changed line 55 from `pathname === '/galaxy'` to `pathname === '/galaxy' || pathname.startsWith('/galaxy/')`
- Changed line 89 to compare pathname instead of lastNavigatedPathRef to preserve query params
**Bug #2: Modal closed when clicking nodes**
- Refactored ThoughtGalaxy to use URL query params (?node=xxx) instead of route params (/galaxy/node:xxx)
- This prevents component unmounting when switching between nodes
- Deleted app/galaxy/[node-id]/page.tsx (no longer needed)
- Updated app/galaxy/page.tsx with documentation comment
- Modified ThoughtGalaxy to:
- Use useSearchParams() hook
- Get selectedNodeId from query params
- Update URL with query params on node click (doesn't cause remount)
- Clear query params when modal closes
**Testing:**
- Verified manually with Playwright MCP that /galaxy?node=xxx preserves query params
- Verified state machine correctly recognizes galaxy state
- Created comprehensive Playwright test suite in tests/playwright/galaxy.spec.ts
**Files changed:**
- components/AppStateMachine.tsx: Fixed state machine to handle /galaxy/* paths and preserve query params
- components/ThoughtGalaxy.tsx: Refactored to use query params instead of route params
- app/galaxy/page.tsx: Added documentation
- app/galaxy/[node-id]/page.tsx: Deleted (replaced with query param approach)
- tests/playwright/galaxy.spec.ts: Added comprehensive test suite
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
