feat: add Go server implementation in go-server/

Full Go port of local-mcp with all core features. Copied from local-mcp-go
worktree to consolidate into single-branch repo (easier maintenance).
Architecture:
- internal/config:  Environment variable configuration
- internal/models:  Shared types (Instruction, Settings, AgentActivity, etc.)
- internal/db:      SQLite init with modernc.org/sqlite (pure Go, no CGo)
- internal/store:   Database operations + WakeupSignal + AgentTracker
- internal/events:  SSE broker for browser /api/events endpoint
- internal/mcp:     get_user_request MCP tool with 5s keepalive progress bars
- internal/api:     chi HTTP router with Bearer auth middleware
- main.go:          Entry point with auto port switching and Windows interactive banner
Dependencies:
- github.com/mark3labs/mcp-go@v0.46.0
- github.com/go-chi/chi/v5@v5.2.5
- modernc.org/sqlite@v1.47.0  (pure Go SQLite)
- github.com/google/uuid@v1.6.0
Static assets embedded via //go:embed static
Features matching Python:
- Same wait strategy: 50s with 5s progress keepalives
- Same hardcoded constants (DEFAULT_WAIT_SECONDS, DEFAULT_EMPTY_RESPONSE)
- Auto port switching (tries 8000-8009)
- Windows interactive mode (formatted banner on double-click launch)
Build:  cd go-server && go build -o local-mcp.exe .
Run:    ./local-mcp.exe
Binary size: ~18 MB (vs Python ~60+ MB memory footprint)
Startup:     ~10 ms (vs Python ~1-2s)

go-server/.gitignore.go

@@ -0,0 +1,32 @@
+# Python
+__pycache__/
+*.py[cod]
+*.pyo
+.venv/
+venv/
+*.egg-info/
+dist/
+build/
+
+# Go
+local-mcp
+local-mcp.exe
+
+# Data
+data/
+
+# Logs
+logs/
+*.log
+server.log
+server_err.log
+
+# IDE
+.idea/
+.vscode/
+*.iml
+
+# OS
+.DS_Store
+Thumbs.db
+