Add comprehensive tests for vector/semantic search functionality

- Implement full coverage tests for Embedder model loading and embedding generation
- Add CRUD operations and caching tests for VectorStore
- Include cosine similarity computation tests
- Validate semantic search accuracy and relevance through various queries
- Establish performance benchmarks for embedding and search operations
- Ensure edge cases and error handling are covered
- Test thread safety and concurrent access scenarios
- Verify availability of semantic search dependencies

.claude/rules/cli-tools-usage.md

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+# CLI Tools Usage Rules
+
+## Tool Selection
+
+### Gemini & Qwen
+**Use for**: Analysis, documentation, code exploration, architecture review
+- Default MODE: `analysis` (read-only)
+- Prefer Gemini; use Qwen as fallback
+- Large context window, pattern recognition
+
+### Codex
+**Use for**: Feature implementation, bug fixes, autonomous development
+- Requires explicit `--mode auto` or `--mode write`
+- Best for: Implementation, testing, automation
+
+## Core Principles
+
+- Use tools early and often - tools are faster and more thorough
+- Always use `ccw cli exec` for consistent parameter handling
+- ALWAYS reference exactly ONE template in RULES section
+- Require EXPLICIT `--mode write` or `--mode auto` for modifications
+- NEVER use escape characters (`\$`, `\"`, `\'`) in CLI commands
+
+## Permission Framework
+
+- `analysis` (default): Read-only, safe for auto-execution
+- `write`: Requires explicit `--mode write` - creates/modifies/deletes files
+- `auto`: Requires explicit `--mode auto` - full autonomous operations (Codex only)
+
+## Timeout Guidelines
+
+- Simple (5-10min): Analysis, search
+- Medium (10-20min): Refactoring, documentation
+- Complex (20-60min): Implementation, migration
+- Heavy (60-120min): Large codebase, multi-file operations
+- Codex multiplier: 3x allocated time (minimum 15min)