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/daemon/daemon.go

@@ -752,8 +752,14 @@ func (d *Daemon) restartPolecatSession(rigName, polecatName, sessionName string)
 		return fmt.Errorf("cannot restart polecat: %s", reason)
 	}
 
-	// Determine working directory
-	workDir := filepath.Join(d.config.TownRoot, rigName, "polecats", polecatName)
+	// Determine working directory (handle both new and old structures)
+	// New structure: polecats/<name>/<rigname>/
+	// Old structure: polecats/<name>/
+	workDir := filepath.Join(d.config.TownRoot, rigName, "polecats", polecatName, rigName)
+	if _, err := os.Stat(workDir); os.IsNotExist(err) {
+		// Fall back to old structure
+		workDir = filepath.Join(d.config.TownRoot, rigName, "polecats", polecatName)
+	}
 
 	// Verify the worktree exists
 	if _, err := os.Stat(workDir); os.IsNotExist(err) {