Add organizing files into Artist/Album/01 Title from their tags

A new Organize tab renames audio files from their tags into a per-pair
naming pattern, by default {artist}/{album}/{track} {title} (album
artist, falling back to artist). Multi-disc albums get a disc prefix
(2-04) or a Disc N folder; names are made safe for Windows/SMB shares.

- Preview first: every rename, files already organized, and files
  skipped with the reason (missing tags, with a button into the tag
  editor; two files resolving to the same name; an existing file).
- Applying re-checks each file against the preview, moves it within its
  library (hardlinks and contents untouched, case-only renames via a
  temporary name, completed on startup after a crash), carries .lrc
  lyrics and folder cover art along, and removes emptied folders. Each
  move is an operation that can be undone; the library is rescanned.
- Optional automatic organizing of the slave, master or both during
  scans (off by default). Dry run applies.
- Scans now recognise a slave file that is a hardlink of a master file
  at a different path as linked ("same file, other path") instead of
  unmatched.

Migration 7 adds the per-pair naming settings.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/store/models.go

@@ -149,6 +149,9 @@ type Pair struct {
 	SettleMinutes       int       `json:"settle_minutes"`
 	ApproxMatching      bool      `json:"approx_matching"`
 	ApproxThreshold     int       `json:"approx_threshold"` // percent
+	OrganizeTemplate    string    `json:"organize_template"`
+	OrganizeMultiDisc   string    `json:"organize_multidisc"` // prefix, folder or none
+	AutoOrganize        string    `json:"auto_organize"`      // off, slave, master or both
 	LastScanAt          *int64    `json:"last_scan_at"`
 	LastScanError       string    `json:"last_scan_error"`
 	LastScanWarnings    []Warning `json:"last_scan_warnings"`
@@ -156,7 +159,8 @@ type Pair struct {
 }
 
 const pairCols = `id, name, master_root, slave_root, quarantine_dir, extensions, auto_link_identical,
-	scan_interval_minutes, retention_days, settle_minutes, approx_matching, approx_threshold, last_scan_at, last_scan_error,
+	scan_interval_minutes, retention_days, settle_minutes, approx_matching, approx_threshold, organize_template,
+	organize_multidisc, auto_organize, last_scan_at, last_scan_error,
 	last_scan_warnings, created_at`
 
 type scanner interface{ Scan(...any) error }
@@ -166,7 +170,8 @@ func scanPair(r scanner) (Pair, error) {
 	var exts, warns string
 	var last sql.NullInt64
 	err := r.Scan(&p.ID, &p.Name, &p.MasterRoot, &p.SlaveRoot, &p.QuarantineDir, &exts, &p.AutoLinkIdentical,
-		&p.ScanIntervalMinutes, &p.RetentionDays, &p.SettleMinutes, &p.ApproxMatching, &p.ApproxThreshold, &last, &p.LastScanError,
+		&p.ScanIntervalMinutes, &p.RetentionDays, &p.SettleMinutes, &p.ApproxMatching, &p.ApproxThreshold, &p.OrganizeTemplate,
+		&p.OrganizeMultiDisc, &p.AutoOrganize, &last, &p.LastScanError,
 		&warns, &p.CreatedAt)
 	if err != nil {
 		return p, err
@@ -208,10 +213,12 @@ func (s *Store) SavePair(ctx context.Context, p *Pair) error {
 	exts := strings.Join(p.Extensions, ",")
 	if p.ID == 0 {
 		res, err := s.DB.ExecContext(ctx, `INSERT INTO pairs (name, master_root, slave_root, quarantine_dir, extensions,
-			auto_link_identical, scan_interval_minutes, retention_days, settle_minutes, approx_matching, approx_threshold, created_at)
-			VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
+			auto_link_identical, scan_interval_minutes, retention_days, settle_minutes, approx_matching, approx_threshold,
+			organize_template, organize_multidisc, auto_organize, created_at)
+			VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
 			p.Name, p.MasterRoot, p.SlaveRoot, p.QuarantineDir, exts, p.AutoLinkIdentical,
-			p.ScanIntervalMinutes, p.RetentionDays, p.SettleMinutes, p.ApproxMatching, p.ApproxThreshold, now())
+			p.ScanIntervalMinutes, p.RetentionDays, p.SettleMinutes, p.ApproxMatching, p.ApproxThreshold,
+			p.OrganizeTemplate, p.OrganizeMultiDisc, p.AutoOrganize, now())
 		if err != nil {
 			return err
 		}
@@ -220,9 +227,10 @@ func (s *Store) SavePair(ctx context.Context, p *Pair) error {
 	}
 	_, err := s.DB.ExecContext(ctx, `UPDATE pairs SET name = ?, master_root = ?, slave_root = ?, quarantine_dir = ?,
 		extensions = ?, auto_link_identical = ?, scan_interval_minutes = ?, retention_days = ?, settle_minutes = ?,
-		approx_matching = ?, approx_threshold = ? WHERE id = ?`,
+		approx_matching = ?, approx_threshold = ?, organize_template = ?, organize_multidisc = ?, auto_organize = ? WHERE id = ?`,
 		p.Name, p.MasterRoot, p.SlaveRoot, p.QuarantineDir, exts, p.AutoLinkIdentical,
-		p.ScanIntervalMinutes, p.RetentionDays, p.SettleMinutes, p.ApproxMatching, p.ApproxThreshold, p.ID)
+		p.ScanIntervalMinutes, p.RetentionDays, p.SettleMinutes, p.ApproxMatching, p.ApproxThreshold,
+		p.OrganizeTemplate, p.OrganizeMultiDisc, p.AutoOrganize, p.ID)
 	return err
 }
 
@@ -266,6 +274,7 @@ const (
 	KindFuzzy     = "fuzzy"       // same directory, normalized title matches
 	KindElsewhere = "elsewhere"   // same top-level folder and title, different subfolder
 	KindApprox    = "approximate" // opt-in: similar title, disc folders ignored
+	KindInode     = "inode"       // the same file (hardlink) at another path
 	KindNone      = "none"
 )
 
@@ -655,6 +664,7 @@ const (
 	ActRemove  = "remove"  // slave hardlink removed (master copy kept)
 	ActRename  = "rename"  // slave folder renamed to the master's spelling
 	ActTags    = "tags"    // tags of a file edited
+	ActMove    = "move"    // file renamed/moved by the organizer
 )
 
 // Operation statuses.