feat: implement agent-notify CLI with hooks and tmux passthrough

Add OSC 777 notification sender, Cursor/Claude hook adapters,
config/install commands, and README for Ghostty + tmux setup.

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

internal/hook/hook_test.go

@@ -0,0 +1,47 @@
+package hook
+
+import (
+	"bytes"
+	"encoding/json"
+	"strings"
+	"testing"
+
+	"github.com/longbin/agent-notify/internal/config"
+)
+
+func TestCursorStopHookDisabled(t *testing.T) {
+	cfg := config.Default()
+	cfg.Events.Stop = false
+	err := RunCursor(bytes.NewReader([]byte(`{"workspace_roots":["/tmp/proj"]}`)), cfg, "stop", &bytes.Buffer{})
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestClaudeStopOutputsTerminalSequence(t *testing.T) {
+	cfg := config.Default()
+	var out bytes.Buffer
+	err := RunClaude(strings.NewReader(`{"stop_hook_active":false}`), cfg, "stop", &out)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var resp map[string]string
+	if err := json.Unmarshal(out.Bytes(), &resp); err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(resp["terminalSequence"], "777;notify") {
+		t.Fatalf("bad sequence: %v", resp)
+	}
+}
+
+func TestClaudeStopHookActiveSkips(t *testing.T) {
+	cfg := config.Default()
+	var out bytes.Buffer
+	err := RunClaude(strings.NewReader(`{"stop_hook_active":true}`), cfg, "stop", &out)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if strings.TrimSpace(out.String()) != "{}" {
+		t.Fatalf("expected {}, got %q", out.String())
+	}
+}