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/internal/api/router.go

@@ -0,0 +1,85 @@
+// Package api implements the REST HTTP endpoints served alongside the MCP server.
+package api
+
+import (
+	"encoding/json"
+	"io/fs"
+	"net/http"
+	"time"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/go-chi/chi/v5/middleware"
+
+	"github.com/local-mcp/local-mcp-go/internal/events"
+	"github.com/local-mcp/local-mcp-go/internal/store"
+)
+
+// Stores groups all database stores that the API handlers need.
+type Stores struct {
+	Instructions *store.InstructionStore
+	Settings     *store.SettingsStore
+	Agents       *store.AgentStore
+}
+
+// NewRouter builds and returns the main chi router.
+// staticFS must serve the embedded static directory; pass nil to skip.
+func NewRouter(stores Stores, broker *events.Broker, apiToken string, staticFS fs.FS) http.Handler {
+	r := chi.NewRouter()
+
+	r.Use(middleware.RealIP)
+	r.Use(middleware.Recoverer)
+
+	// Auth-check endpoint — always public
+	r.Get("/auth-check", func(w http.ResponseWriter, r *http.Request) {
+		writeJSON(w, http.StatusOK, map[string]any{
+			"auth_required": apiToken != "",
+		})
+	})
+
+	// Health — always public
+	r.Get("/healthz", handleHealth())
+
+	// Static files — always public
+	if staticFS != nil {
+		r.Get("/", func(w http.ResponseWriter, r *http.Request) {
+			http.ServeFileFS(w, r, staticFS, "index.html")
+		})
+		r.Handle("/static/*", http.StripPrefix("/static/", http.FileServerFS(staticFS)))
+	}
+
+	// All /api/* routes are protected when apiToken is set
+	r.Group(func(r chi.Router) {
+		if apiToken != "" {
+			r.Use(bearerAuthMiddleware(apiToken))
+		}
+		r.Get("/api/status", handleStatus(stores))
+		r.Get("/api/instructions", handleListInstructions(stores))
+		r.Post("/api/instructions", handleCreateInstruction(stores, broker))
+		r.Patch("/api/instructions/{id}", handleUpdateInstruction(stores, broker))
+		r.Delete("/api/instructions/consumed", handleClearConsumed(stores, broker))
+		r.Delete("/api/instructions/{id}", handleDeleteInstruction(stores, broker))
+		r.Get("/api/config", handleGetConfig(stores))
+		r.Patch("/api/config", handleUpdateConfig(stores, broker))
+		r.Get("/api/events", handleSSE(broker))
+	})
+
+	return r
+}
+
+// writeJSON serialises v as JSON with the given status code.
+func writeJSON(w http.ResponseWriter, status int, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	_ = json.NewEncoder(w).Encode(v)
+}
+
+// writeError writes a JSON {"detail": msg} error response.
+func writeError(w http.ResponseWriter, status int, msg string) {
+	writeJSON(w, status, map[string]string{"detail": msg})
+}
+
+// serverStartTime records when this process started, used by /api/status.
+var serverStartTime = time.Now().UTC()
+
+
+