Go HTTP server skeleton with router and graceful shutdown

[tayebmokni]

Summary

Build the minimal Go HTTP server skeleton that boots, serves on a configurable port, and exposes a routable handler chain. This is the chassis subsequent issues mount handlers onto.

Design reference

• docs/00-architecture-overview.md §4 (System Topology — Go API Server)
• docs/00-architecture-overview.md §2 (Stack Decisions)

Acceptance criteria

• cmd/server/main.go starts an HTTP server on a port read from env (default 8080)
• Uses chi or stdlib net/http with a router; routes are registered in internal/http
• Graceful shutdown on SIGINT/SIGTERM with a 10s timeout
• Structured logging via slog with JSON output
• GET / returns 200 with a JSON {"name":"gonext","version":"<commit>"} payload
• Unit test verifies server starts, responds to root, and shuts down cleanly

Dependencies

#1

Complexity

S