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/client/client.go

@@ -0,0 +1,111 @@
+package client
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"strings"
+	"time"
+
+	"task/internal/daemon/api"
+)
+
+// Client talks to the local JSON daemon over a Unix socket.
+type Client struct {
+	http   *http.Client
+	kind   string // tui | cli | mcp
+	token  string // bearer for mcp
+	project string // mcp bound project
+}
+
+// Options configures a daemon client.
+type Options struct {
+	Socket  string
+	Kind    string
+	Token   string
+	Project string
+}
+
+// Dial creates a client for the given Unix socket.
+func Dial(opts Options) *Client {
+	kind := opts.Kind
+	if kind == "" {
+		kind = api.ClientTUI
+	}
+	return &Client{
+		kind:    kind,
+		token:   opts.Token,
+		project: opts.Project,
+		http: &http.Client{
+			Timeout: 60 * time.Second,
+			Transport: &http.Transport{
+				DialContext: func(ctx context.Context, _, _ string) (net.Conn, error) {
+					var d net.Dialer
+					return d.DialContext(ctx, "unix", opts.Socket)
+				},
+			},
+		},
+	}
+}
+
+func (c *Client) do(method, path string, in any, out any) error {
+	var body io.Reader
+	if in != nil {
+		b, err := json.Marshal(in)
+		if err != nil {
+			return err
+		}
+		body = bytes.NewReader(b)
+	}
+	req, err := http.NewRequest(method, "http://daemon"+path, body)
+	if err != nil {
+		return err
+	}
+	if in != nil {
+		req.Header.Set("Content-Type", "application/json")
+	}
+	req.Header.Set(api.HeaderClient, c.kind)
+	if c.kind == api.ClientMCP {
+		if c.token != "" {
+			req.Header.Set("Authorization", "Bearer "+c.token)
+		}
+		if c.project != "" {
+			req.Header.Set("X-TM-Project", c.project)
+		}
+	}
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	data, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return err
+	}
+	if resp.StatusCode >= 400 {
+		var er struct {
+			Error string `json:"error"`
+		}
+		_ = json.Unmarshal(data, &er)
+		if er.Error == "" {
+			er.Error = strings.TrimSpace(string(data))
+		}
+		if er.Error == "" {
+			er.Error = resp.Status
+		}
+		return fmt.Errorf("%s", er.Error)
+	}
+	if out == nil || resp.StatusCode == http.StatusNoContent || len(data) == 0 {
+		return nil
+	}
+	return json.Unmarshal(data, out)
+}
+
+// Health checks /v1/health.
+func (c *Client) Health() error {
+	return c.do(http.MethodGet, "/v1/health", nil, nil)
+}