docs: add comprehensive data schema and query taxonomy for agent use

docs: add GCAS_DATA_SCHEMA.md — full schema reference for agents

docs: update README and main.py to reflect two-tier architecture (v2.0.0)

fix: normalizer over-expansion + stopword keyword filter + intent/program coverage

fix: taluka entity causing district filter to reject correct college rows

feat: rethink architecture — structured lookup replaces FAISS as primary path

fix: college entity hard-filter after FAISS to fix wrong-college results

feat: college keyword lookup, smart result count, field filtering, context window optimisation

feat: intent detection, field filtering, table routing, post-filters

feat: Hindi/Gujarati query fixes + smart result count + deduplication

fix: restrict entity rewriting to districts/talukas only

add bearer token auth to /search and /reindex

initial deploy