docs: expand README and documentation for production release

- Update README.md status from 'educational proof-of-concept' to 'production-ready'
- Fix binary size: 286KB -> 3.3MB
- Update test count: 162/35 -> 262/56
- Add sections: benchmarks, Docker, clients, security, config, monitoring, backup, cross-modal queries, troubleshooting
- Expand project structure with all 49 modules and ~14,100 LOC
- Add 10 new docs: performance, deployment, configuration, clients, security, monitoring, backup, crossmodal, troubleshooting, changelog
- Expand docs/en: architecture, baraql, installation, protocol
- Update docs/bg: architecture, installation
- Update docs/index.md with new links
- Update .gitignore for __pycache__, rust/target, nim binaries

docs/index.md

@@ -15,11 +15,14 @@
 - [Installation](en/installation.md)
 - [Quick Start](en/quickstart.md)
 - [Architecture Overview](en/architecture.md)
+- [Configuration Reference](en/configuration.md)
+- [Deployment Guide](en/deployment.md)
 
 ### Core Concepts
 - [BaraQL Query Language](en/baraql.md)
 - [Storage Engines](en/storage.md)
 - [Schema System](en/schema.md)
+- [Cross-Modal Queries](en/crossmodal.md)
 
 ### Engines
 - [LSM-Tree Storage](en/lsm.md)
@@ -29,25 +32,33 @@
 - [Full-Text Search](en/fts.md)
 - [Columnar Storage](en/columnar.md)
 
-### Advanced
-- [Transactions & MVCC](en/transactions.md)
-- [Distributed Systems](en/distributed.md)
-- [Protocol Reference](en/protocol.md)
-- [User Defined Functions](en/udf.md)
-
-### API Reference
+### API & Clients
+- [Client SDKs](en/clients.md)
 - [Binary Protocol](en/api-binary.md)
 - [HTTP/REST API](en/api-http.md)
 - [WebSocket API](en/api-websocket.md)
+- [Protocol Reference](en/protocol.md)
+
+### Operations
+- [Performance & Benchmarks](en/performance.md)
+- [Security Guide](en/security.md)
+- [Monitoring & Observability](en/monitoring.md)
+- [Backup & Recovery](en/backup.md)
+- [Troubleshooting](en/troubleshooting.md)
+
+### Advanced
+- [Transactions & MVCC](en/transactions.md)
+- [Distributed Systems](en/distributed.md)
+- [User Defined Functions](en/udf.md)
 
 ---
 
 ## Project Info
 
-- [Contributing](../CONTRIBUTING.md)
+- [Changelog](en/changelog.md)
 - [License](../LICENSE)
 - [GitHub Repository](https://github.com/katehonz/barabaDB)
 
 ---
 
-*To add a new language, create a new folder in `docs/` with the language code (e.g., `docs/de/`) and add a link above.*
+*To add a new language, create a new folder in `docs/` with the language code (e.g., `docs/de/`) and add a link above.*