refactor(scheduler): migrate from per-user to system-wide scan settings

Update scheduler to use system-wide settings instead of per-user:
- Change Database interface to use GetSystemSetting
- Remove GetScanSettings (per-user method)
- Update checkAndScheduleScans to read system settings
- Apply system-wide scan frequency to all libraries

Scheduler now respects global scan settings for all library scanning,
enabling consistent system-wide scan behavior.

internal/services/scheduler.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"strconv"
 	"sync"
 	"time"
 
@@ -24,16 +25,11 @@ type Scheduler struct {
 }
 
 type Database interface {
-	GetScanSettings(ctx context.Context, id pgtype.UUID) (database.GetScanSettingsRow, error)
+	GetSystemSetting(ctx context.Context, settingKey string) (string, error)
 	ListLibraries(ctx context.Context) ([]database.ListLibrariesRow, error)
 	GetLibraryFolders(ctx context.Context, libraryID pgtype.UUID) ([]database.LibraryFolders, error)
 }
 
-type ScanSettingRow struct {
-	ScanFrequencyMinutes pgtype.Int4
-	AutoScanEnabled      pgtype.Bool
-}
-
 type Library struct {
 	ID   pgtype.UUID
 	Name string
@@ -111,32 +107,53 @@ func (s *Scheduler) checkAndScheduleScans() {
 		return
 	}
 
+	autoScanEnabledStr, err := s.db.GetSystemSetting(ctx, "auto_scan_enabled")
+	if err != nil {
+		log.Printf("Error getting auto_scan_enabled setting: %v", err)
+		return
+	}
+
+	autoScanEnabled, err := strconv.ParseBool(autoScanEnabledStr)
+	if err != nil {
+		log.Printf("Error parsing auto_scan_enabled: %v", err)
+		return
+	}
+
+	if !autoScanEnabled {
+		return
+	}
+
+	scanFrequencyStr, err := s.db.GetSystemSetting(ctx, "scan_frequency_minutes")
+	if err != nil {
+		log.Printf("Error getting scan_frequency_minutes setting: %v", err)
+		return
+	}
+
+	scanFrequency, err := strconv.Atoi(scanFrequencyStr)
+	if err != nil {
+		log.Printf("Error parsing scan_frequency_minutes: %v", err)
+		return
+	}
+
+	if scanFrequency < 15 {
+		return
+	}
+
 	for _, library := range libraries {
-		settings, err := s.db.GetScanSettings(ctx, library.ID)
-		if err != nil {
-			libraryIDStr := fmt.Sprintf("%x", library.ID.Bytes)
-			log.Printf("Error getting scan settings for library %s: %v", libraryIDStr, err)
-			continue
-		}
-
-		if !settings.AutoScanEnabled.Bool || settings.ScanFrequencyMinutes.Int32 < 15 {
-			continue
-		}
-
-		userID := fmt.Sprintf("%x", library.ID.Bytes)
+		libraryIDStr := fmt.Sprintf("%x", library.ID.Bytes)
 
 		s.mu.Lock()
-		currentSetting, exists := s.scanSettings[userID]
+		currentSetting, exists := s.scanSettings[libraryIDStr]
 		scanSetting := ScanSetting{
-			UserID:    userID,
-			Enabled:   settings.AutoScanEnabled.Bool,
-			Frequency: int(settings.ScanFrequencyMinutes.Int32),
+			UserID:    libraryIDStr,
+			Enabled:   autoScanEnabled,
+			Frequency: scanFrequency,
 		}
-		s.scanSettings[userID] = scanSetting
+		s.scanSettings[libraryIDStr] = scanSetting
 		s.mu.Unlock()
 
 		if !exists || currentSetting.Frequency != scanSetting.Frequency {
-			s.scheduleLibraryScan(ctx, library.ID, userID, scanSetting.Frequency)
+			s.scheduleLibraryScan(ctx, library.ID, libraryIDStr, scanSetting.Frequency)
 		}
 	}
 }