route bank_panel bank-op persists through persistBankOp so panel gestures get undo points like the bindable actions

src/actions.h

@@ -66,4 +66,13 @@ bool bankHandleCommand(int command);
 // rec==nullptr (before g_session is torn down).
 void bankUnregisterActions(reaper_plugin_info_t* rec);
 
+// Persists a completed bank-index verb as a single REAPER undo point (R-B).
+// Wraps persistBook() (= SetProjExtState) in a Begin/End block with UNDO_STATE_MISCCFG
+// so the bank op is one Ctrl-Z. On an unsaved / no-active project persistBook() no-ops
+// and the block is closed with an empty label + zero flag (REAPER discards it). Callers
+// must invoke this ONLY after a successful/effective mutation — rejected ops (duplicate
+// name, un-deletable pool, etc.) must return before reaching here so no empty undo
+// point is ever opened for a no-op. Defined in actions.cpp alongside persistBook().
+void persistBankOp(const char* label);
+
 }  // namespace reasampler