Finalize i18n, AI coach, receipt scanning, and UI polish for hackathon submission

Add local AI mode and insight coach

Harden demo flow and surface Modal status

Bypass FastAPI validation for Modal parse

Fix Modal parse request injection

Accept flexible Modal parse payloads

Add pandas to Modal image

Bake VoiceLedger source into Modal image

Package VoiceLedger sources for Modal

Fix voice transcription handling

Add Nemotron parser provider

Integrate Modal backend