feat: add Cursor IDE support with pre-translated configs

Add complete .cursor/ directory with rules, agents, skills, commands,
and MCP config adapted for Cursor's format. This makes ecc-universal
a truly cross-IDE package supporting Claude Code, Cursor, and OpenCode.

- 27 rule files with YAML frontmatter (description, globs, alwaysApply)
- 13 agent files with full model IDs and readonly flags
- 30 skill directories (identical Agent Skills standard, no translation)
- 31 command files (5 multi-* stubbed for missing codeagent-wrapper)
- MCP config with Cursor env interpolation syntax
- README.md and MIGRATION.md documentation
- install.sh --target cursor flag for project-scoped installation
- package.json updated with .cursor/ in files and cursor keywords

.cursor/commands/test-coverage.md

@@ -0,0 +1,27 @@
+# Test Coverage
+
+Analyze test coverage and generate missing tests:
+
+1. Run tests with coverage: npm test --coverage or pnpm test --coverage
+
+2. Analyze coverage report (coverage/coverage-summary.json)
+
+3. Identify files below 80% coverage threshold
+
+4. For each under-covered file:
+   - Analyze untested code paths
+   - Generate unit tests for functions
+   - Generate integration tests for APIs
+   - Generate E2E tests for critical flows
+
+5. Verify new tests pass
+
+6. Show before/after coverage metrics
+
+7. Ensure project reaches 80%+ overall coverage
+
+Focus on:
+- Happy path scenarios
+- Error handling
+- Edge cases (null, undefined, empty)
+- Boundary conditions