feat: add LLM integration for patent analysis

Implemented LLMAnalyzer class using Anthropic's Claude API for:
- Single patent content analysis
- Portfolio-wide analysis across multiple patents
- Configurable API key management via environment variables

Key features:
- Uses Claude 3.5 Sonnet for high-quality analysis
- Structured prompts for innovation assessment
- Token limits optimized per use case (1024 for single, 2048 for portfolio)
- Analyzes: innovation quality, market potential, strategic direction

Updated config.py to support ANTHROPIC_API_KEY environment variable.

Added comprehensive test suite (6 tests) covering:
- Initialization from config and direct API key
- Single patent analysis
- Portfolio analysis
- Token limit validation

All 19 tests passing.

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

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

requirements.txt

@@ -4,3 +4,4 @@ pdfplumber
 requests
 pytest
 pytest-mock
+anthropic