feat: implement comprehensive thinking modes and migrate to google-genai

Major improvements to thinking capabilities and API integration:

- Remove all output token limits for future-proof responses
- Add 5-level thinking mode system: minimal, low, medium, high, max
- Migrate from google-generativeai to google-genai library
- Implement native thinkingBudget support for Gemini 2.5 Pro
- Set medium thinking as default for all tools, max for think_deeper

🧠 Thinking Modes:
- minimal (128 tokens) - simple tasks
- low (2048 tokens) - basic reasoning
- medium (8192 tokens) - default for most tools
- high (16384 tokens) - complex analysis
- max (32768 tokens) - default for think_deeper

🔧 Technical Changes:
- Complete migration to google-genai>=1.19.0
- Remove google-generativeai dependency
- Add ThinkingConfig with thinking_budget parameter
- Update all tools to support thinking_mode parameter
- Comprehensive test suite with 37 passing unit tests
- CI-friendly testing (no API key required for unit tests)
- Live integration tests for API verification

🧪 Testing & CI:
- Add GitHub Actions workflow with multi-Python support
- Unit tests use mocks, no API key required
- Live integration tests optional with API key
- Contributing guide with development setup
- All tests pass without external dependencies

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

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

.github/workflows/test.yml

@@ -1,82 +1,87 @@
-name: Test
+name: Tests
 
 on:
   push:
-    branches: [ main ]
+    branches: [ main, develop ]
   pull_request:
     branches: [ main ]
 
 jobs:
   test:
-    runs-on: ${{ matrix.os }}
+    runs-on: ubuntu-latest
     strategy:
-      fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: ['3.10', '3.11', '3.12']
+        python-version: ["3.10", "3.11", "3.12"]
 
     steps:
     - uses: actions/checkout@v4
-
+    
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v4
       with:
         python-version: ${{ matrix.python-version }}
-
+    
     - name: Install dependencies
       run: |
-        python -m pip install --upgrade pip setuptools wheel
-        pip install -e .
+        python -m pip install --upgrade pip
         pip install -r requirements.txt
-
-    - name: Run tests with pytest
-      env:
-        GEMINI_API_KEY: "dummy-key-for-tests"
-        PYTHONPATH: ${{ github.workspace }}
+    
+    - name: Run unit tests
       run: |
-        python -m pytest tests/ -v --cov=gemini_server --cov-report=xml --cov-report=term -x
-
+        # Run all tests except live integration tests
+        # These tests use mocks and don't require API keys
+        python -m pytest tests/ --ignore=tests/test_live_integration.py -v --cov=. --cov-report=xml
+      env:
+        # Ensure no API key is accidentally used in CI
+        GEMINI_API_KEY: ""
+    
     - name: Upload coverage to Codecov
-      if: matrix.os == 'ubuntu-latest' && matrix.python-version == '3.11'
-      uses: codecov/codecov-action@v4
+      uses: codecov/codecov-action@v3
       with:
         file: ./coverage.xml
-        flags: unittests
-        name: codecov-umbrella
-        fail_ci_if_error: false
+        fail_ci_if_error: true
 
   lint:
     runs-on: ubuntu-latest
-    
     steps:
     - uses: actions/checkout@v4
     
     - name: Set up Python
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v4
       with:
-        python-version: '3.11'
+        python-version: "3.11"
     
     - name: Install dependencies
       run: |
-        python -m pip install --upgrade pip setuptools wheel
-        pip install flake8 black isort mypy
+        python -m pip install --upgrade pip
+        pip install ruff black
+    
+    - name: Run black formatter check
+      run: black --check .
+    
+    - name: Run ruff linter
+      run: ruff check .
+
+  live-tests:
+    runs-on: ubuntu-latest
+    # Only run live tests if API key secret is available
+    if: github.event_name == 'push' && github.ref == 'refs/heads/main' && secrets.GEMINI_API_KEY != ''
+    steps:
+    - uses: actions/checkout@v4
+    
+    - name: Set up Python
+      uses: actions/setup-python@v4
+      with:
+        python-version: "3.11"
+    
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
         pip install -r requirements.txt
     
-    - name: Lint with flake8
+    - name: Run live integration tests
       run: |
-        # Stop the build if there are Python syntax errors or undefined names
-        flake8 gemini_server.py --count --select=E9,F63,F7,F82 --show-source --statistics
-        # exit-zero treats all errors as warnings
-        flake8 gemini_server.py --count --exit-zero --max-complexity=10 --max-line-length=120 --statistics
-    
-    - name: Check formatting with black
-      run: |
-        black --check gemini_server.py
-    
-    - name: Check import order with isort
-      run: |
-        isort --check-only gemini_server.py
-    
-    - name: Type check with mypy
-      run: |
-        mypy gemini_server.py --ignore-missing-imports
+        # Run live tests that make actual API calls
+        python tests/test_live_integration.py
+      env:
+        GEMINI_API_KEY: ${{ secrets.GEMINI_API_KEY }}