Implement database migration framework and performance optimizations

- Added active memory configuration for manual interval and Gemini tool.
- Created file modification rules for handling edits and writes.
- Implemented migration manager for managing database schema migrations.
- Added migration 001 to normalize keywords into separate tables.
- Developed tests for validating performance optimizations including keyword normalization, path lookup, and symbol search.
- Created validation script to manually verify optimization implementations.

.claude/rules/context-requirements.md

@@ -5,3 +5,42 @@ Before implementation, always:
 - Identify 3+ existing similar patterns before implementation
 - Map dependencies and integration points
 - Understand testing framework and coding conventions
+
+## Context Gathering
+
+### Use Exa
+- Researching external APIs, libraries, frameworks
+- Need recent documentation beyond knowledge cutoff
+- Looking for implementation examples in public repos
+- User mentions specific library/framework names
+- Questions about "best practices" or "how does X work"
+
+### Use read_file (MCP)
+- Reading multiple related files at once
+- Directory traversal with pattern matching
+- Searching file content with regex
+- Need to limit depth/file count for large directories
+- Batch operations on multiple files
+- Pattern-based filtering (glob + content regex)
+
+### Use codex_lens
+- Large codebase (>500 files) requiring repeated searches
+- Need semantic understanding of code relationships
+- Working across multiple sessions
+- Symbol-level navigation needed
+- Finding all implementations of interface/class
+- Tracking function calls across codebase
+
+### Use smart_search
+- Unknown file locations
+- Concept/semantic search ("authentication logic", "payment processing")
+- Medium-sized codebase (100-500 files)
+- One-time or infrequent searches
+- Natural language queries about code structure
+
+**Mode Selection**:
+- `auto`: Let tool decide (default)
+- `exact`: Known exact pattern
+- `fuzzy`: Typo-tolerant search
+- `semantic`: Concept-based search
+- `graph`: Dependency analysis