docs: update README and all docs with formal verification, new BaraQL features, OpenTelemetry tracing

- Add Formal Verification section to README and architecture docs
- Document TLA+ specs for Raft, 2PC, MVCC, Replication
- Add new BaraQL features: JSON path (->, ->>), FTS @@, CREATE INDEX USING FTS,
  RECOVER TO TIMESTAMP, UNION/INTERSECT/EXCEPT
- Add OpenTelemetry tracing example to README
- Update Quick Start to use nimble test/bench
- Update EN and BG documentation

docs/en/architecture.md

@@ -133,6 +133,7 @@ Client → Protocol → Auth → Parser → AST → IR → Codegen
 5. **MVCC**: Multi-version concurrency control
 6. **Schema-First**: Strongly typed schema system with inheritance
 7. **Cross-Modal**: Single query language across all data models
+8. **Formally Verified**: Core distributed algorithms specified in TLA+ and model-checked with TLC
 
 ## Module Statistics