chore: consolidate env files and update gitignore

Removed .env and .env.backup from git tracking and consolidated configuration into .env.example. Updated .gitignore to robustly prevent accidental inclusion of sensitive files.

TODO.md

@@ -7,12 +7,15 @@
 - [x] Auth Middleware
 - [x] Basic Provider implementations (OpenAI, Gemini, DeepSeek, Grok)
 - [x] Streaming Support (SSE & Gemini custom streaming)
-- [x] Move Rust files to `rust_backup`
+- [x] Archive Rust files to `rust` branch
+- [x] Clean root and set Go version as `main`
 - [x] Enhanced `helpers.go` for Multimodal & Tool Calling (OpenAI compatible)
 - [x] Enhanced `server.go` for robust request conversion
 - [x] Dashboard Management APIs (Clients, Tokens, Users, Providers)
 - [x] Dashboard Analytics & Usage Summary
 - [x] WebSocket for real-time dashboard updates
+- [x] Asynchronous Request Logging to SQLite
+- [x] Update documentation (README, deployment, architecture)
 
 ## Feature Parity Checklist (High Priority)
 
@@ -38,10 +41,9 @@
 - [x] Multimodal support
 
 ## Infrastructure & Middleware
-- [ ] Implement Request Logging to SQLite (asynchronous)
 - [ ] Implement Rate Limiting (`golang.org/x/time/rate`)
 - [ ] Implement Circuit Breaker (`github.com/sony/gobreaker`)
-- [ ] Implement Model Cost Calculation logic
+- [ ] Implement Model Cost Calculation logic (needs registry/pricing integration)
 
 ## Verification
 - [ ] Unit tests for feature-specific mapping (CoT, Tools, Images)