feat: IGLA API Server Cycle 19 — OpenAI-Compatible HTTP/REST Interface

Adds local HTTP/REST API server with OpenAI-compatible endpoints for external access.

Key features:
- OpenAI-compatible /v1/chat/completions endpoint
- /v1/models, /health, /metrics endpoints
- Local HTTP server (configurable port 8080)
- CORS support for browser clients
- SSE streaming mode support
- Request parsing and JSON response building
- Integration with StreamingEngine (Cycle 18)

Benchmark results:
- 112/112 tests passing
- 15,076 requests/second throughput
- 100% success rate
- 66us average response time
- Improvement rate: 1.00 (PASSED > 0.618)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: gHashTag