docs: update documentation for OpenRouter migration

Update all user-facing documentation to reflect the migration from
Anthropic API to OpenRouter.

Changes:
- Update README.md to reference OpenRouter instead of Anthropic in:
  - Features section
  - Architecture diagram comments
  - Configuration instructions
  - API key acquisition links
- Update main.py docstring to use OPENROUTER_API_KEY

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

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

README.md

@@ -13,7 +13,7 @@ SPARC automatically collects, parses, and analyzes patents from companies to pro
 - **Patent Retrieval**: Automated collection via SerpAPI's Google Patents engine
 - **Intelligent Parsing**: Extracts key sections (abstract, claims, summary) from patent PDFs
 - **Content Minimization**: Removes verbose descriptions to reduce LLM token usage
-- **AI Analysis**: Uses Claude 3.5 Sonnet to analyze innovation quality and market potential
+- **AI Analysis**: Uses Claude 3.5 Sonnet via OpenRouter to analyze innovation quality and market potential
 - **Portfolio Analysis**: Evaluates multiple patents holistically for comprehensive insights
 - **Robust Testing**: 26 tests covering all major functionality
 
@@ -22,7 +22,7 @@ SPARC automatically collects, parses, and analyzes patents from companies to pro
 ```
 SPARC/
 ├── serp_api.py       # Patent retrieval and PDF parsing
-├── llm.py            # Claude AI integration for analysis
+├── llm.py            # Claude AI integration via OpenRouter
 ├── analyzer.py       # High-level orchestration
 ├── types.py          # Data models
 └── config.py         # Environment configuration
@@ -54,13 +54,13 @@ Create a `.env` file in the project root:
 # SerpAPI key for patent search
 API_KEY=your_serpapi_key_here
 
-# Anthropic API key for Claude AI analysis
-ANTHROPIC_API_KEY=your_anthropic_key_here
+# OpenRouter API key for Claude AI analysis
+OPENROUTER_API_KEY=your_openrouter_key_here
 ```
 
 Get your API keys:
 - SerpAPI: https://serpapi.com/
-- Anthropic: https://console.anthropic.com/
+- OpenRouter: https://openrouter.ai/
 
 ## Usage
 

main.py

@@ -5,7 +5,7 @@ Example usage of the company performance analyzer.
 Before running:
 1. Create a .env file with:
    API_KEY=your_serpapi_key
-   ANTHROPIC_API_KEY=your_anthropic_key
+   OPENROUTER_API_KEY=your_openrouter_key
 
 2. Run: python main.py
 """