Add local JSON daemon and route TUI/CLI through it.

A per-DataDir background process owns ticket JSON, history, and sync so
multiple TUI instances stay consistent; MCP token APIs are ready for phase 2.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/daemon/serve.go

@@ -0,0 +1,79 @@
+package daemon
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"task/internal/command"
+	"task/internal/config"
+	"task/internal/daemon/api"
+	"task/internal/project"
+	"task/internal/ticket"
+)
+
+// Run starts the foreground daemon for cfg until signal or context cancel.
+func Run(cfg *config.Config) error {
+	abs, err := AbsoluteDataDir(cfg.DataDir)
+	if err != nil {
+		return err
+	}
+	cfg.DataDir = abs
+
+	p, err := PathsForDataDir(cfg.DataDir)
+	if err != nil {
+		return err
+	}
+	cleanupStale(p)
+
+	store := ticket.NewJSONStore(cfg.DataDir)
+	timeStore := ticket.NewJSONTimeStore(cfg.DataDir)
+	projects := project.NewDirStore(cfg.DataDir)
+	history, err := command.OpenHistory(command.HistoryPath(cfg.DataDir), store, timeStore)
+	if err != nil {
+		return fmt.Errorf("history: %w", err)
+	}
+
+	srvAPI := api.New(store, timeStore, projects, history)
+	server := &http.Server{Handler: srvAPI.Handler()}
+
+	ln, err := net.Listen("unix", p.Socket)
+	if err != nil {
+		return fmt.Errorf("listen %s: %w", p.Socket, err)
+	}
+	if err := os.Chmod(p.Socket, 0o600); err != nil {
+		_ = ln.Close()
+		return fmt.Errorf("chmod socket: %w", err)
+	}
+	if err := writePID(p.PIDFile, os.Getpid()); err != nil {
+		_ = ln.Close()
+		return fmt.Errorf("pid file: %w", err)
+	}
+	defer cleanupStale(p)
+
+	errCh := make(chan error, 1)
+	go func() {
+		errCh <- server.Serve(ln)
+	}()
+
+	sigCh := make(chan os.Signal, 1)
+	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
+
+	select {
+	case <-sigCh:
+		ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
+		defer cancel()
+		_ = server.Shutdown(ctx)
+		return nil
+	case err := <-errCh:
+		if err == http.ErrServerClosed {
+			return nil
+		}
+		return err
+	}
+}