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Fix Donut OCR: image preprocessing, CORD→text conversion, better fallback

Fix month resolution: use previous year for future month names

Fix tool schema and relative month handling in QA

Fix UnboundLocalError in QA fallback path

Fix Insights vendor chart ignoring month filter

Fall back to RAG when get_receipt_items returns no structured items

Fix tool_use_failed: keyword fallback executes tool directly, no hallucinated placeholders

Fix 404 on page refresh: add Vercel SPA rewrite rule

Revert to Groq llama-3.3-70b (Gemini free tier quota exhausted)

Fix classifier.py: replace groq import with openai/Gemini

Switch LLM from Groq to Google Gemini 2.0 Flash

Revert to llama-3.3-70b-versatile (3.1 decommissioned by Groq)

Switch Groq model to llama-3.1-70b-versatile for more stable tool calling

Handle Groq tool_use_failed BadRequestError with no-tool fallback