fix: personalized greetings and filtered technical tags

feat: Smart tool results and Mock Memory for Demo

feat: Maya Intelligence & Stability - Smart Availability, Rich Context, and Structured Notes

fix: Full audit round 3 - speechbrain graceful fallback, STT echo bug (remove prompt param), UUID guard in caller_memory

hotfix: Fix STT initial_prompt crash + datetime import + Hindi pronunciation (hun->hoon)

feat(E4): Caller Memory and Real-Time DB Lookups