v0.0.1: versioning reset

Major changes since last build:
- Tool RAG hybrid backend is now the default (was fts) — fixes tool-flood on Italian queries
- Pyodide sandbox runtime removed; replaced by process runner with Python deps baked into image
- Settings UI cut from ~62 rows to the 12 a user actually configures
- Dockerfile installs requests, pandas, openpyxl, python-calamine, etc. so execute_code is useful out of the box
- Dead config fields removed (SpeculativeSearchTimeoutMS, MistralOCRIncludeImages, MaxToolIterations, OCREnabled, SandboxRuntimeMode/URL/Dir)