fix(molecules): cascade-close child wisps on molecule completion (gt-zbnr)

When deacon patrol molecules completed, their child step wisps were not being
closed automatically. This caused orphan wisp accumulation - 143+ orphaned
wisps were found in one cleanup session.

The fix ensures that when a molecule completes (via gt done or gt mol step done),
all descendant step issues are recursively closed before the molecule itself.

Changes:
- done.go: Added closeDescendants() call in updateAgentStateOnDone before
  closing the attached molecule
- molecule_step.go: Added closeDescendants() call in handleMoleculeComplete
  for all roles (not just polecats)

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

internal/cmd/done.go

@@ -608,11 +608,21 @@ func updateAgentStateOnDone(cwd, townRoot, exitType, _ string) { // issueID unus
 			// has attached_molecule pointing to the wisp. Without this fix, gt done
 			// only closed the hooked bead, leaving the wisp orphaned.
 			// Order matters: wisp closes -> unblocks base bead -> base bead closes.
+			//
+			// BUG FIX (gt-zbnr): Close child wisps BEFORE closing the molecule itself.
+			// Deacon patrol molecules have child step wisps that were being orphaned
+			// when the patrol completed. Now we cascade-close all descendants first.
 			attachment := beads.ParseAttachmentFields(hookedBead)
 			if attachment != nil && attachment.AttachedMolecule != "" {
-				if err := bd.Close(attachment.AttachedMolecule); err != nil {
+				moleculeID := attachment.AttachedMolecule
+				// Cascade-close all child wisps before closing the molecule
+				childrenClosed := closeDescendants(bd, moleculeID)
+				if childrenClosed > 0 {
+					fmt.Printf("  Closed %d child step issues\n", childrenClosed)
+				}
+				if err := bd.Close(moleculeID); err != nil {
 					// Non-fatal: warn but continue
-					fmt.Fprintf(os.Stderr, "Warning: couldn't close attached molecule %s: %v\n", attachment.AttachedMolecule, err)
+					fmt.Fprintf(os.Stderr, "Warning: couldn't close attached molecule %s: %v\n", moleculeID, err)
 				}
 			}
 
@@ -645,7 +655,7 @@ func updateAgentStateOnDone(cwd, townRoot, exitType, _ string) { // issueID unus
 		if _, err := bd.Run("agent", "state", agentBeadID, "awaiting-gate"); err != nil {
 			fmt.Fprintf(os.Stderr, "Warning: couldn't set agent %s to awaiting-gate: %v\n", agentBeadID, err)
 		}
-	// ExitCompleted and ExitDeferred don't set state - observable from tmux
+		// ExitCompleted and ExitDeferred don't set state - observable from tmux
 	}
 
 	// ZFC #10: Self-report cleanup status