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
 

docs/en/backup.md

@@ -75,6 +75,14 @@ BARADB_WAL_ARCHIVE_INTERVAL_MS=60000 \
   --target-time="2025-01-15T10:30:00Z"
 ```
 
+### Recovery via SQL
+
+You can also recover directly via BaraQL:
+
+```sql
+RECOVER TO TIMESTAMP '2026-05-07T12:00:00';
+```
+
 ### Incremental Backups
 
 Incremental backups only copy changed SSTables:

docs/en/baraql.md

@@ -22,6 +22,7 @@ BaraQL is a SQL-compatible query language with extensions for graph, vector, and
 | `datetime` | ISO 8601 timestamp | `'2025-01-15T10:30:00Z'` |
 | `uuid` | UUID v4 | `'550e8400-e29b-41d4-a716-446655440000'` |
 | `json` | JSON document | `{"key": "value"}` |
+| `jsonb` | Binary JSON (validated) | `{"key": "value"}` |
 
 ## Basic Queries
 
@@ -360,6 +361,32 @@ DROP TYPE User;
 DROP INDEX idx_users_name;
 ```
 
+### JSON Path Operators
+
+```sql
+-- Extract JSON field as JSON
+SELECT data->'name' FROM users;
+
+-- Extract JSON field as text
+SELECT data->>'name' FROM users;
+```
+
+### Full-Text Search (SQL)
+
+```sql
+-- Create FTS index with BM25
+CREATE INDEX idx_fts ON articles(body) USING FTS;
+
+-- Search with BM25 ranking
+SELECT * FROM articles WHERE body @@ 'machine learning';
+```
+
+### Point-in-Time Recovery
+
+```sql
+RECOVER TO TIMESTAMP '2026-05-07T12:00:00';
+```
+
 ## Vector Search
 
 ```sql
@@ -505,4 +532,7 @@ SELECT /*+ PARALLEL(4) */ * FROM large_table;
 | Graph | MATCH, RETURN, WHERE, shortestPath, type |
 | FTS | MATCH, AGAINST, relevance, IN BOOLEAN MODE, WITH FUZZINESS |
 | Vector | cosine_distance, l2_distance, dot_product, manhattan_distance |
+| JSON | ->, ->> |
+| FTS | @@ (BM25 match) |
+| Recovery | RECOVER TO TIMESTAMP |
 | Functions | count, sum, avg, min, max, stddev, variance, abs, sqrt, lower, upper, len, trim, substr, now, last_insert_id |

docs/en/distributed.md

@@ -87,4 +87,24 @@ import barabadb/core/disttxn
 var dt = newDistributedTxn()
 dt.prepare(@["node1", "node2"])
 dt.commit()
+```
+
+## Formal Verification
+
+Core distributed algorithms are formally specified in TLA+ and model-checked:
+
+- **Raft Consensus** — `formal-verification/raft.tla`
+  - Verified: ElectionSafety, StateMachineSafety
+- **Two-Phase Commit** — `formal-verification/twopc.tla`
+  - Verified: Atomicity, NoOrphanBlocks
+- **Replication** — `formal-verification/replication.tla`
+  - Verified: MonotonicLsn, AcksRemovePending
+
+Run TLC locally:
+
+```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
 ```

docs/en/fts.md

@@ -52,6 +52,24 @@ let tfidf = idx.searchTfidf("query terms")
 | Phrase search | Exact phrase matching |
 | Boolean | AND, OR, NOT operators |
 
+## SQL Interface
+
+Full-text search is also available directly in BaraQL:
+
+```sql
+-- Create a table with text column
+CREATE TABLE articles (id INT PRIMARY KEY, title TEXT, body TEXT);
+
+-- Create an FTS index
+CREATE INDEX idx_fts ON articles(body) USING FTS;
+
+-- Search with the @@ operator (BM25 ranking)
+SELECT * FROM articles WHERE body @@ 'machine learning';
+
+-- Search with multiple terms
+SELECT * FROM articles WHERE body @@ 'quick brown fox';
+```
+
 ## Multi-Language Support
 
 ```nim

docs/en/transactions.md

@@ -58,4 +58,21 @@ Nested transaction savepoints:
 tm.savepoint(txn, "sp1")
 # ... operations ...
 tm.rollbackToSavepoint(txn, "sp1")
+```
+
+## Formal Verification
+
+The MVCC / Snapshot Isolation protocol is formally specified in TLA+:
+
+- **Spec:** `formal-verification/mvcc.tla`
+- **Verified properties:**
+  - `NoDirtyReads` — transactions never read uncommitted data
+  - `ReadOwnWrites` — transactions always see their own writes
+  - `WriteWriteConflict` — first-committer-wins (no two committed transactions write the same key)
+
+Run TLC locally:
+
+```bash
+cd formal-verification
+java -cp tla2tools.jar tlc2.TLC -config models/mvcc.cfg mvcc.tla
 ```