chore: rewrite CLAUDE.md for V3 with correctness invariants

Reduce CLAUDE.md from 577 to 108 lines, refocus on essential guidance:

Removals:
- ~250 lines of RBAC/multi-tenancy/index API examples (belong in module docs)
- Redundant file/ETS table listings
- Pre-V3 configuration details

Additions:
- V3 state machine shape and 6 correctness invariants:
  * Deterministic replay via meta.system_time
  * No anonymous functions in Raft state/log
  * All mutations routed through Raft consensus
  * ETS as materialized views
  * Snapshots via release_cursor effects
  * Pre-consensus evaluation for CAS operations
- Module responsibility table
- Links to architectural docs in docs/ directory

Better signal-to-noise for future implementers working with Raft consensus.

Author: GSMLG-BOT