feat: add comprehensive test suite, CI/CD workflows, and install command

Major improvements to SuperClaude Framework infrastructure and testing:

## New Features
- Add 'superclaude install' command to install slash commands (/research, /index-repo, /agent, /recommend)
- Create comprehensive test suite with 71 tests (70 passing, 1 skipped)
- Add GitHub Actions CI/CD workflows for automated testing
- Add essential documentation files (PLANNING.md, TASK.md, KNOWLEDGE.md)

## Testing
- tests/unit/: 59 tests covering PM Agent components
  - test_confidence.py: 13 tests for ConfidenceChecker
  - test_self_check.py: 14 tests for SelfCheckProtocol
  - test_reflexion.py: 9 tests for ReflexionPattern
  - test_token_budget.py: 12 tests for TokenBudgetManager
  - test_cli_install.py: 12 tests for install command (NEW)
- tests/integration/: 11 tests for pytest plugin integration
- tests/conftest.py: Shared fixtures for all tests

## CI/CD Workflows
- .github/workflows/test.yml: Comprehensive test matrix
  - Tests on Python 3.10, 3.11, 3.12
  - Lint and format checks with ruff
  - Pytest plugin verification
  - SuperClaude doctor health checks
  - Coverage reporting with Codecov
- .github/workflows/quick-check.yml: Fast PR validation (~2-3 min)
- .github/workflows/README.md: Workflow documentation

## Documentation
- PLANNING.md: Architecture, design principles, absolute rules
- TASK.md: Current tasks, priorities, backlog
- KNOWLEDGE.md: Accumulated insights, best practices, troubleshooting

## Bug Fixes
- Fix .gitignore contradictions (remove conflicting Claude Code patterns)
- Fix TokenBudgetManager to properly validate and default invalid complexity
- Update package.json version to 4.1.6 (sync with VERSION file)

## CLI Improvements
- src/superclaude/cli/install_commands.py: Command installation logic
- src/superclaude/cli/main.py: Add 'install' command with --list and --force options
- README.md: Update installation instructions with correct commands

## Breaking Changes
None - all changes are backwards compatible

## Migration Guide
Users should run 'superclaude install' after upgrading to install slash commands

Fixes #466 (indirectly by clarifying installation process)
Refs #419 (plugin system - documentation updated)

🤖 Generated with Claude Code

Co-Authored-By: Claude <noreply@anthropic.com>

tests/__init__.py

@@ -0,0 +1,10 @@
+"""
+SuperClaude Framework Test Suite
+
+Test organization:
+- unit/ - Unit tests for individual components
+- integration/ - Integration tests for component interactions
+- fixtures/ - Shared test fixtures and helpers
+"""
+
+__version__ = "0.4.0"