fix(polecat): kill orphan sessions and clear stale hooks during allocation (#448)

ReconcilePool now detects and kills orphan tmux sessions (sessions without
corresponding polecat directories). This prevents allocation from being
blocked by broken state from crashed polecats.

Changes:
- Add tmux to Manager to check for orphan sessions during reconciliation
- Add ReconcilePoolWith for testable session/directory reconciliation logic
- Always clear hook_bead slot when reopening agent beads (fixes stale hooks)
- Prune stale git worktree entries during reconciliation

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

internal/cmd/polecat_identity.go

@@ -221,7 +221,8 @@ func runPolecatIdentityAdd(cmd *cobra.Command, args []string) error {
 	// Generate name if not provided
 	if polecatName == "" {
 		polecatGit := git.NewGit(r.Path)
-		mgr := polecat.NewManager(r, polecatGit)
+		t := tmux.NewTmux()
+		mgr := polecat.NewManager(r, polecatGit, t)
 		polecatName, err = mgr.AllocateName()
 		if err != nil {
 			return fmt.Errorf("generating polecat name: %w", err)
@@ -294,7 +295,7 @@ func runPolecatIdentityList(cmd *cobra.Command, args []string) error {
 
 		// Check if worktree exists
 		worktreeExists := false
-		mgr := polecat.NewManager(r, nil)
+		mgr := polecat.NewManager(r, nil, t)
 		if p, err := mgr.Get(name); err == nil && p != nil {
 			worktreeExists = true
 		}
@@ -396,7 +397,7 @@ func runPolecatIdentityShow(cmd *cobra.Command, args []string) error {
 	// Check worktree and session
 	t := tmux.NewTmux()
 	polecatMgr := polecat.NewSessionManager(t, r)
-	mgr := polecat.NewManager(r, nil)
+	mgr := polecat.NewManager(r, nil, t)
 
 	worktreeExists := false
 	var clonePath string