Add test coverage for daemon lifecycle and config modules

- Add config_test.go: tests for daemon configuration (local/global, sync behavior)
- Add daemon_test.go: tests for daemon lifecycle (creation, shutdown, database path resolution)
- Add process_test.go: tests for daemon lock acquisition and release
- Closes bd-2b34.6, bd-2b34.7

Amp-Thread-ID: https://ampcode.com/threads/T-4419d1ab-4105-4e75-bea8-1837ee80e2c2
Co-authored-by: Amp <amp@ampcode.com>

internal/daemonrunner/process_test.go

@@ -0,0 +1,118 @@
+package daemonrunner
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestDaemonLockBasics(t *testing.T) {
+	tmpDir := t.TempDir()
+	dbPath := filepath.Join(tmpDir, "beads.db")
+
+	// Acquire lock
+	lock, err := acquireDaemonLock(tmpDir, dbPath, "0.19.0")
+	if err != nil {
+		t.Fatalf("Failed to acquire lock: %v", err)
+	}
+	defer lock.Close()
+
+	// Verify lock file was created
+	lockPath := filepath.Join(tmpDir, "daemon.lock")
+	if _, err := os.Stat(lockPath); os.IsNotExist(err) {
+		t.Error("Lock file was not created")
+	}
+
+	// Verify PID file was created
+	pidPath := filepath.Join(tmpDir, "daemon.pid")
+	if _, err := os.Stat(pidPath); os.IsNotExist(err) {
+		t.Error("PID file was not created")
+	}
+
+	// Read and verify lock metadata
+	data, err := os.ReadFile(lockPath)
+	if err != nil {
+		t.Fatalf("Failed to read lock file: %v", err)
+	}
+
+	var info DaemonLockInfo
+	if err := json.Unmarshal(data, &info); err != nil {
+		t.Fatalf("Failed to parse lock file: %v", err)
+	}
+
+	if info.PID != os.Getpid() {
+		t.Errorf("Expected PID %d, got %d", os.Getpid(), info.PID)
+	}
+	if info.Database != dbPath {
+		t.Errorf("Expected database %s, got %s", dbPath, info.Database)
+	}
+	if info.Version != "0.19.0" {
+		t.Errorf("Expected version 0.19.0, got %s", info.Version)
+	}
+	if info.StartedAt.IsZero() {
+		t.Error("Expected non-zero StartedAt timestamp")
+	}
+}
+
+func TestDaemonLockExclusive(t *testing.T) {
+	tmpDir := t.TempDir()
+	dbPath := filepath.Join(tmpDir, "beads.db")
+
+	// Acquire first lock
+	lock1, err := acquireDaemonLock(tmpDir, dbPath, "0.19.0")
+	if err != nil {
+		t.Fatalf("Failed to acquire first lock: %v", err)
+	}
+	defer lock1.Close()
+
+	// Try to acquire second lock (should fail)
+	lock2, err := acquireDaemonLock(tmpDir, dbPath, "0.19.0")
+	if err != ErrDaemonLocked {
+		if lock2 != nil {
+			lock2.Close()
+		}
+		t.Errorf("Expected ErrDaemonLocked, got %v", err)
+	}
+}
+
+func TestDaemonLockRelease(t *testing.T) {
+	tmpDir := t.TempDir()
+	dbPath := filepath.Join(tmpDir, "beads.db")
+
+	// Acquire lock
+	lock, err := acquireDaemonLock(tmpDir, dbPath, "0.19.0")
+	if err != nil {
+		t.Fatalf("Failed to acquire lock: %v", err)
+	}
+
+	// Release lock
+	if err := lock.Close(); err != nil {
+		t.Fatalf("Failed to release lock: %v", err)
+	}
+
+	// Should be able to acquire again after release
+	lock2, err := acquireDaemonLock(tmpDir, dbPath, "0.19.0")
+	if err != nil {
+		t.Fatalf("Failed to acquire lock after release: %v", err)
+	}
+	defer lock2.Close()
+}
+
+func TestDaemonLockCloseIdempotent(t *testing.T) {
+	tmpDir := t.TempDir()
+	dbPath := filepath.Join(tmpDir, "beads.db")
+
+	lock, err := acquireDaemonLock(tmpDir, dbPath, "0.19.0")
+	if err != nil {
+		t.Fatalf("Failed to acquire lock: %v", err)
+	}
+
+	// Close multiple times should not error
+	if err := lock.Close(); err != nil {
+		t.Errorf("First close failed: %v", err)
+	}
+	if err := lock.Close(); err != nil {
+		t.Errorf("Second close failed: %v", err)
+	}
+}