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/bg/distributed.md

@@ -34,4 +34,24 @@ import barabadb/core/replication
 var rm = newReplicationManager(rmSync)
 rm.addReplica(newReplica("r1", "10.0.0.1", 9472))
 rm.connectReplica("r1")
+```
+
+## Формална Верификация
+
+Разпределените алгоритми са формално специфицирани в TLA+ и проверени с TLC:
+
+- **Raft Консенсус** — `formal-verification/raft.tla`
+  - Проверено: ElectionSafety, StateMachineSafety
+- **Two-Phase Commit** — `formal-verification/twopc.tla`
+  - Проверено: Atomicity, NoOrphanBlocks
+- **Репликация** — `formal-verification/replication.tla`
+  - Проверено: MonotonicLsn, AcksRemovePending
+
+Пускане на TLC:
+
+```bash
+cd formal-verification
+java -cp tla2tools.jar tlc2.TLC -config models/raft.cfg raft.tla
+java -cp tla2tools.jar tlc2.TLC -config models/twopc.cfg twopc.tla
+java -cp tla2tools.jar tlc2.TLC -config models/replication.cfg replication.tla
 ```