feat: add full directory support and smart file handling

Major improvements to file handling capabilities:

- Add directory traversal support to all file-processing tools
- Tools now accept both individual files and entire directories
- Automatically expand directories and discover code files recursively
- Smart filtering: skip hidden files, __pycache__, and non-code files
- Progressive token loading: read as many files as possible within limits
- Clear file separation markers with full paths for Gemini

Key changes:
- Rewrite file_utils.py with expand_paths() and improved read_files()
- Update all tool descriptions to indicate directory support
- Add comprehensive tests for directory handling and token limits
- Document tool parameters and examples in README
- Bump version to 2.4.2

All tools (analyze, review_code, debug_issue, think_deeper) now support:
- Single files: "analyze main.py"
- Directories: "review src/"
- Mixed paths: "analyze config.py, src/, tests/"

This enables analyzing entire projects or specific subsystems efficiently
while respecting token limits and providing clear file boundaries.

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

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

utils/__init__.py

@@ -2,12 +2,14 @@
 Utility functions for Gemini MCP Server
 """
 
-from .file_utils import read_file_content, read_files
+from .file_utils import read_file_content, read_files, expand_paths, CODE_EXTENSIONS
 from .token_utils import check_token_limit, estimate_tokens
 
 __all__ = [
     "read_files",
     "read_file_content",
+    "expand_paths",
+    "CODE_EXTENSIONS",
     "estimate_tokens",
     "check_token_limit",
 ]