feat(polecat): add repo path to worktrees for LLM ergonomics (GH#283)

Changes polecat worktree structure from:
  polecats/<name>/
to:
  polecats/<name>/<rigname>/

This gives Claude Code agents a recognizable directory name (e.g., tidepool/)
in their cwd instead of just the polecat name, preventing confusion about
which repo they are working in.

Key changes:
- Add clonePath() method to manager.go and session_manager.go for the actual
  git worktree path, keeping polecatDir() for existence checks
- Update Add(), RepairWorktree(), Remove() to use new structure
- Update daemon lifecycle and restart code for new paths
- Update witness handlers to detect both structures
- Update doctor checks (rig_check, branch_check, config_check,
  claude_settings_check) for backward compatibility
- All code includes fallback to old structure for existing polecats

Fixes #283

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/cmd/polecat.go

@@ -579,7 +579,7 @@ func runPolecatSync(cmd *cobra.Command, args []string) error {
 		polecatName = ""
 	}
 
-	mgr, r, err := getPolecatManager(rigName)
+	mgr, _, err := getPolecatManager(rigName)
 	if err != nil {
 		return err
 	}
@@ -606,10 +606,15 @@ func runPolecatSync(cmd *cobra.Command, args []string) error {
 	// Sync each polecat
 	var syncErrors []string
 	for _, name := range polecatsToSync {
-		polecatDir := filepath.Join(r.Path, "polecats", name)
+		// Get polecat to get correct clone path (handles old vs new structure)
+		p, err := mgr.Get(name)
+		if err != nil {
+			syncErrors = append(syncErrors, fmt.Sprintf("%s: %v", name, err))
+			continue
+		}
 
 		// Check directory exists
-		if _, err := os.Stat(polecatDir); os.IsNotExist(err) {
+		if _, err := os.Stat(p.ClonePath); os.IsNotExist(err) {
 			syncErrors = append(syncErrors, fmt.Sprintf("%s: directory not found", name))
 			continue
 		}
@@ -623,7 +628,7 @@ func runPolecatSync(cmd *cobra.Command, args []string) error {
 		fmt.Printf("Syncing %s/%s...\n", rigName, name)
 
 		syncCmd := exec.Command("bd", syncArgs...)
-		syncCmd.Dir = polecatDir
+		syncCmd.Dir = p.ClonePath
 		output, err := syncCmd.CombinedOutput()
 		if err != nil {
 			syncErrors = append(syncErrors, fmt.Sprintf("%s: %v", name, err))