Reorganize Firefox configuration and repository documentation

- Configure Firefox with privacy settings and extensions (Bitwarden, Plasma Integration, MetaMask, Kagi Search, uBlock Origin)
- Set Kagi as default/only search engine
- Add MOZ_USE_XINPUT2=1 for smooth scrolling
- Create context/ directory for concise unit documentation
- Create tests/ directory for test scripts
- Move test-firefox-config.sh to tests/
- Update agents.md with documentation workflow guidelines
- Fix syntax errors in desktop.nix and dev.nix

context/firefox-initial-setup.md

@@ -0,0 +1,52 @@
+# Firefox Initial Privacy Setup
+
+**User:** jsutter  
+**Config:** `users/jsutter.nix` → `programs.firefox`
+
+## Privacy Configuration
+
+### Privacy Policies (Locked)
+- Password manager: Disabled
+- Password saving: Disabled
+- Form history: Disabled
+- Telemetry: Disabled
+- Firefox Studies: Disabled
+- CaptivePortal: Disabled
+
+### Homepage & Privacy
+- Search: Disabled and locked
+- Top Sites/Highlights/Snippets: Disabled
+- Recommendations: Disabled (extensions, features)
+
+### Content Blocking
+- Mode: Strict
+- Tracking protection: Enabled (social, fingerprinting, cryptomining)
+- Do Not Track: Enabled
+- Fingerprinting resistance: Enabled
+
+### Permissions (Block All)
+- Location requests
+- Notification requests
+- Autoplay (audio/video)
+- Virtual Reality requests
+
+### Data Collection
+- Sanitize on shutdown: Enabled (cache, cookies, history, etc.)
+- Private attribution: Disabled
+- Battery API: Disabled
+
+## Build & Verify
+```bash
+nixos-rebuild build --flake .#framework
+sudo nixos-rebuild switch --flake .
+```
+
+## Verification URLs
+- `about:policies` - Active policies
+- `about:preferences#privacy` - Privacy settings
+- `about:preferences#home` - Homepage/new tab settings
+
+## Notes
+- Original extensions: uBlock Origin, Privacy Badger, Facebook Container, Multi-account Containers
+- All privacy settings declaratively managed via Home Manager
+- Settings persist across Firefox updates