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

tests/README.md

@@ -0,0 +1,76 @@
+# Tests Directory
+
+This directory contains test scripts for verifying NixOS configurations.
+
+## Purpose
+Automated verification of system configurations to catch issues before deployment.
+
+## Available Tests
+
+### Firefox Configuration Test
+**Script:** `test-firefox-config.sh`
+
+Verifies Firefox Home Manager configuration for user `jsutter`:
+- Environment variables (`MOZ_USE_XINPUT2`)
+- Policy file existence and validity
+- Extension policies
+- Profile preferences
+- Privacy settings
+
+**Usage:**
+```bash
+./test-firefox-config.sh
+```
+
+**Requirements:**
+- Firefox installed
+- Valid Home Manager configuration
+- JSON parsing tool (`jq` or Python)
+
+## Running Tests
+
+### All Tests
+```bash
+tests/test-firefox-config.sh
+```
+
+### Specific Test
+```bash
+./tests/test-firefox-config.sh
+```
+
+## Test Conventions
+
+### Shell Scripts
+- Use `set -e` for error handling
+- Define colored output for readability
+- Track pass/fail/skip counts
+- Return non-zero on failure
+- Use helper functions (`print_pass`, `print_fail`, etc.)
+
+### Test Coverage
+Tests should verify:
+- Configuration builds successfully
+- Policies are active (`about:policies`)
+- Settings are enforced
+- Extensions are force-installed
+- User preferences are applied
+
+## Adding New Tests
+
+1. Create test script in `tests/`
+2. Make executable: `chmod +x tests/new-test.sh`
+3. Document in this README
+4. Follow naming convention: `test-<service>.sh`
+
+## Notes
+
+- Many tests require services to be deployed first
+- Some Firefox tests require Firefox to have been run once
+- Automated tests complement manual verification
+- Update test scripts when configurations change
+
+## Related Documentation
+
+- `context/` - Configuration documentation
+- `agents.md` - Agent procedures