Refactor daemon.go for testability and maintainability (bd-2b34)

- Split 1567-line daemon.go into 5 focused modules
- daemon_config.go (122 lines): config/path resolution
- daemon_lifecycle.go (451 lines): start/stop/status/health/metrics
- daemon_sync.go (510 lines): export/import/sync logic
- daemon_server.go (115 lines): RPC server setup
- daemon_logger.go (43 lines): logging utilities
- Reduced main daemon.go to 389 lines (75% reduction)
- All tests pass, improved code organization

Amp-Thread-ID: https://ampcode.com/threads/T-7504c501-f962-4b82-a6d9-8e33f547757d
Co-authored-by: Amp <amp@ampcode.com>

cmd/bd/daemon_config.go

@@ -0,0 +1,122 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strconv"
+
+	"github.com/steveyegge/beads"
+)
+
+// getGlobalBeadsDir returns the global beads directory (~/.beads)
+func getGlobalBeadsDir() (string, error) {
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return "", fmt.Errorf("cannot get home directory: %w", err)
+	}
+
+	beadsDir := filepath.Join(home, ".beads")
+	if err := os.MkdirAll(beadsDir, 0700); err != nil {
+		return "", fmt.Errorf("cannot create global beads directory: %w", err)
+	}
+
+	return beadsDir, nil
+}
+
+// ensureBeadsDir ensures the local beads directory exists (.beads in the current workspace)
+func ensureBeadsDir() (string, error) {
+	var beadsDir string
+	if dbPath != "" {
+		beadsDir = filepath.Dir(dbPath)
+	} else {
+		// Use public API to find database (same logic as other commands)
+		if foundDB := beads.FindDatabasePath(); foundDB != "" {
+			dbPath = foundDB // Store it for later use
+			beadsDir = filepath.Dir(foundDB)
+		} else {
+			// No database found - error out instead of falling back to ~/.beads
+			return "", fmt.Errorf("no database path configured (run 'bd init' or set BEADS_DB)")
+		}
+	}
+
+	if err := os.MkdirAll(beadsDir, 0700); err != nil {
+		return "", fmt.Errorf("cannot create beads directory: %w", err)
+	}
+
+	return beadsDir, nil
+}
+
+// boolToFlag returns the flag string if condition is true, otherwise returns empty string
+func boolToFlag(condition bool, flag string) string {
+	if condition {
+		return flag
+	}
+	return ""
+}
+
+// getEnvInt reads an integer from environment variable with a default value
+func getEnvInt(key string, defaultValue int) int {
+	if val := os.Getenv(key); val != "" {
+		if parsed, err := strconv.Atoi(val); err == nil {
+			return parsed
+		}
+	}
+	return defaultValue
+}
+
+// getEnvBool reads a boolean from environment variable with a default value
+func getEnvBool(key string, defaultValue bool) bool {
+	if val := os.Getenv(key); val != "" {
+		return val == "true" || val == "1"
+	}
+	return defaultValue
+}
+
+// getSocketPathForPID determines the socket path for a given PID file
+func getSocketPathForPID(pidFile string, global bool) string {
+	if global {
+		home, _ := os.UserHomeDir()
+		return filepath.Join(home, ".beads", "bd.sock")
+	}
+	// Local daemon: socket is in same directory as PID file
+	return filepath.Join(filepath.Dir(pidFile), "bd.sock")
+}
+
+// getPIDFilePath returns the path to the daemon PID file
+func getPIDFilePath(global bool) (string, error) {
+	var beadsDir string
+	var err error
+
+	if global {
+		beadsDir, err = getGlobalBeadsDir()
+	} else {
+		beadsDir, err = ensureBeadsDir()
+	}
+
+	if err != nil {
+		return "", err
+	}
+	return filepath.Join(beadsDir, "daemon.pid"), nil
+}
+
+// getLogFilePath returns the path to the daemon log file
+func getLogFilePath(userPath string, global bool) (string, error) {
+	if userPath != "" {
+		return userPath, nil
+	}
+
+	var beadsDir string
+	var err error
+
+	if global {
+		beadsDir, err = getGlobalBeadsDir()
+	} else {
+		beadsDir, err = ensureBeadsDir()
+	}
+
+	if err != nil {
+		return "", err
+	}
+	return filepath.Join(beadsDir, "daemon.log"), nil
+}