Overhauled the README files (en and zh) to improve user experience based on a detailed analysis of the project's functionality and MCP best practices.

Key changes include:
- **Clarified Tooling**: Removed non-existent `search_code` tool and renamed `search_code_advanced` to `search_code` for simplicity. Added the `refresh_search_tools` utility.
- **Improved Setup Instructions**: Restructured the setup guide to provide clear, use-case-driven instructions for general users, local developers, and manual installers.
- **Logical Workflow**: Re-wrote the usage examples into a step-by-step workflow, introducing the concept of indexing and refreshing for better user understanding.

Add detail for Claude Code

Update README.md

This commit refactors the internal `file_index` data structure to be more explicit and robust, preventing a `KeyError` crash in the `find_files` tool.

Previously, the `file_index` was inconsistent: file entries were marked with "type": "file", but directory entries were implicitly represented by a plain dictionary, lacking a `type` key. This led to errors in functions like `_get_all_files` that incorrectly assumed the `type` key would always be present.

This has been resolved by:
- Modifying `_index_project` to explicitly add {"type": "directory", "children": {}} for all directory entries.
- Updating the helper functions (`_get_all_files`, `_count_files`) to correctly parse this new, consistent structure.
- Adding backward-compatibility in `set_project_path` to handle old-format index files by gracefully triggering a re-index if loading fails.

This change makes the indexing logic more maintainable and less prone to errors.

Fixes the first part of #10.

This commit addresses the file_pattern issues reported in GitHub issue #10
regarding inconsistent behavior across different search strategies.

Changes:
- Fix UgrepStrategy: Use -g option instead of incorrect --include format
- Fix BasicSearchStrategy: Add proper glob pattern matching with fnmatch
- Fix BasicSearchStrategy: Correct newline stripping (use '\n' not '\\n')
- Improve BasicSearchStrategy error handling with specific exception types
- Enhance search_code_advanced docstring with detailed tool behavior documentation

The search_code_advanced tool now provides comprehensive documentation
about how different search tools handle file patterns and fuzzy matching,
helping LLMs understand the differences between:
- ugrep: Native glob support and fuzzy search
- ripgrep: Good glob and regex support
- ag: Converts globs to regex (may have limitations)
- grep: Standard glob support
- basic: Fallback with full glob support via fnmatch

This ensures file_pattern parameters like "src/*.py" work consistently
across all available search strategies.

Related to #10

This commit addresses the file_pattern issues reported in GitHub issue #10
regarding inconsistent behavior across different search strategies.

Changes:
- Fix UgrepStrategy: Use -g option instead of incorrect --include format
- Fix BasicSearchStrategy: Add proper glob pattern matching with fnmatch
- Fix BasicSearchStrategy: Correct newline stripping (use '\n' not '\\n')
- Improve BasicSearchStrategy error handling with specific exception types
- Enhance search_code_advanced docstring with detailed tool behavior documentation

The search_code_advanced tool now provides comprehensive documentation
about how different search tools handle file patterns and fuzzy matching,
helping LLMs understand the differences between:
- ugrep: Native glob support and fuzzy search
- ripgrep: Good glob and regex support  
- ag: Converts globs to regex (may have limitations)
- grep: Standard glob support
- basic: Fallback with full glob support via fnmatch

This ensures file_pattern parameters like "src/*.py" work consistently
across all available search strategies.

Related to #10