Add max_tokens parameter to NexAGI endpoint

Add privacy column to Document model + migration 005

Fix NexAGIResponse: reasoning_details is list[dict], not dict

Fix NexAGI: reasoning_details list model_dump, add reasoning_details to message schema

Add /NexAGI endpoint — OpenRouter reasoning via nex-agi/nex-n2-pro:free

feat: provider-based LLM profiles + per-request model switching

feat: add page_width/page_height to citations for frontend bbox scaling + combined bbox+dimension extraction

feat: on-demand pdfplumber bbox extraction for citation highlighting

feat: add username field to User model, schemas, and API

fix: import parse_document outside .pdf scope; coerce datetime→str in all response schemas

fix: remove local file fallback, use Cloudinary only, add POST /documents/backfill endpoint for old docs

fix: add file_url to every citation so the frontend PDF viewer gets the URL directly without extra API call

fix: add file_url to DocumentResponse, pass request to _doc_response, handle old-path files in serve_file

fix: normalize filenames (space/underscore) for doc counting in analyze tab, add document_id to Citation model

feat: /analyze now fairly samples all selected documents, adds cross_document_comparison + per_document_summary fields to response

fix models.py: match Neon schema varchar sizes, add email unique constraint