feat: Vercel-ready OpenCouncil with 3 cities connected (Paris, Sulphur Springs, Frisco)

Implement Three P's framework: Life-Centric categories, Big Picture TL;DR, What You Can Do

fix: align DeepSeek JSON output schema with frontend TypeScript interfaces

feat: improve OCR preprocessing pipeline with upscaling, deskew, Otsu threshold, morphology, and multi-PSM Tesseract strategy

Add pre-computed OCR database for Paris city council minutes

Fix Vercel backend 500 errors