refactor: remove MCP code-index dependency, replace with ripgrep/find

Replace all mcp__code-index__ calls with native ripgrep and find commands
across workflow and command files for better performance and portability.

Changes:
- Remove 41 mcp__code-index__ function calls from 12 files
- Replace with ripgrep (rg) for content search
- Replace with find for file discovery
- Remove index refresh dependencies (no longer needed)

Modified files:
- workflow/tools: context-gather, test-context-gather, task-generate-agent,
  task-generate, test-task-generate (core workflow tools)
- workflow: review (security scanning)
- memory: load, update-related, docs (memory management)
- cli/mode: plan, bug-index, code-analysis (CLI modes)

Documentation updates:
- Simplify mcp-tool-strategy.md to only Exa usage (5 lines)
- Streamline context-search-strategy.md to 69 lines
- Standardize codebase-retrieval syntax per intelligent-tools-strategy.md

Benefits:
- Faster search with ripgrep (no index overhead)
- Better cross-platform compatibility
- Simpler configuration (fewer MCP dependencies)
- -232 lines of code removed

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

.claude/commands/memory/load.md

@@ -121,14 +121,14 @@ Task(
 ### Step 2: Keyword Extraction & File Discovery
 
 1. Extract core keywords from task description
-2. Discover relevant files using MCP code-index or rg:
-   \`\`\`javascript
-   // Prefer MCP tools
-   mcp__code-index__find_files(pattern="*{keyword}*")
-   mcp__code-index__search_code_advanced(pattern="{keyword}", context_lines=2)
+2. Discover relevant files using ripgrep and find:
+   \`\`\`bash
+   # Find files by name
+   find . -name "*{keyword}*" -type f
 
-   // Fallback: use rg
-   bash(rg -l "{keyword}" --type ts --type md)
+   # Search content with ripgrep
+   rg "{keyword}" --type ts --type md -C 2
+   rg -l "{keyword}" --type ts --type md  # List files only
    \`\`\`
 
 ### Step 3: Deep Analysis via CLI