fix(parser): export and variable mappings for graceful fallbacks

feat: complete backend engine logic (llm parsing, puppeteer renderer, sqlite analytics)

fix: resolve HF build - ESLint rule and img tags

fix: remove eslint-disable directives for unloaded rules in pdf.ts

fix: simplify ESLint directive to resolve HF build error

fix: resolve pdf-parse webpack build error on Hugging Face

fix: resolve TypeScript and test configuration issues for Phase 13