feat: extension button placement, text extraction, OCR display + ML improvements

Fix: Overhaul Facebook post detection to filtered comments using [role='feed'] strategy and improve button positioning

fix(extension): exclude comment articles from Facebook post detection

feat: oEmbed scraping for Facebook/X URLs, remove social URL blocks

fix(extension): init() no longer exits when service worker returns undefined

feat(extension): convert popup to persistent side panel

fix(extension): block social URLs in popup, show paste-text hint

fix(extension): insert missing PLATFORM_CFG/CFG/IS_SOCIAL config block

feat(extension): X/Twitter support, image OCR fallback, cleanup IS_FACEBOOK

feat(extension): production API URL, PH news site support, article auto-verify

fix: cold start 502, favicon, verify state persistence