Enable Purge More / Resume with EP + Host Prompt (#21671)

Co-authored-by: Msq001 <alansayyeah@gmail.com>

Marlin/src/feature/host_actions.cpp

         switch (response) {
 
           case 0: // "Purge More" button
-            #if BOTH(HAS_LCD_MENU, ADVANCED_PAUSE_FEATURE)
+            #if BOTH(M600_PURGE_MORE_RESUMABLE, ADVANCED_PAUSE_FEATURE)
               pause_menu_response = PAUSE_RESPONSE_EXTRUDE_MORE;  // Simulate menu selection (menu exits, doesn't extrude more)
             #endif
             break;
 
           case 1: // "Continue" / "Disable Runout" button
-            #if BOTH(HAS_LCD_MENU, ADVANCED_PAUSE_FEATURE)
+            #if BOTH(M600_PURGE_MORE_RESUMABLE, ADVANCED_PAUSE_FEATURE)
               pause_menu_response = PAUSE_RESPONSE_RESUME_PRINT;  // Simulate menu selection
             #endif
             #if HAS_FILAMENT_SENSOR

Marlin/src/feature/pause.cpp

 
 static xyze_pos_t resume_position;
 
-#if HAS_LCD_MENU
+#if M600_PURGE_MORE_RESUMABLE
   PauseMenuResponse pause_menu_response;
   PauseMode pause_mode = PAUSE_MODE_PAUSE_PRINT;
 #endif
 
       TERN_(HOST_PROMPT_SUPPORT, filament_load_host_prompt()); // Initiate another host prompt.
 
-      #if HAS_LCD_MENU
+      #if M600_PURGE_MORE_RESUMABLE
         if (show_lcd) {
           // Show "Purge More" / "Resume" menu and wait for reply
           KEEPALIVE_STATE(PAUSED_FOR_USER);
           wait_for_user = false;
-          ui.pause_show_message(PAUSE_MESSAGE_OPTION);
+          #if HAS_LCD_MENU
+            ui.pause_show_message(PAUSE_MESSAGE_OPTION); // Also sets PAUSE_RESPONSE_WAIT_FOR
+          #else
+            pause_menu_response = PAUSE_RESPONSE_WAIT_FOR;
+          #endif
           while (pause_menu_response == PAUSE_RESPONSE_WAIT_FOR) idle_no_sleep();
         }
       #endif
 
       // Keep looping if "Purge More" was selected
-    } while (TERN0(HAS_LCD_MENU, show_lcd && pause_menu_response == PAUSE_RESPONSE_EXTRUDE_MORE));
+    } while (TERN0(M600_PURGE_MORE_RESUMABLE, show_lcd && pause_menu_response == PAUSE_RESPONSE_EXTRUDE_MORE));
 
   #endif
   TERN_(HOST_PROMPT_SUPPORT, host_action_prompt_end());

Marlin/src/feature/pause.h

   PAUSE_MESSAGE_HEATING
 };
 
-#if HAS_LCD_MENU
+#if M600_PURGE_MORE_RESUMABLE
   enum PauseMenuResponse : char {
     PAUSE_RESPONSE_WAIT_FOR,
     PAUSE_RESPONSE_EXTRUDE_MORE,

Marlin/src/inc/Conditionals_post.h

   #define HEATER_IDLE_HANDLER 1
 #endif
 
-#if ENABLED(ADVANCED_PAUSE_FEATURE) && !defined(FILAMENT_CHANGE_SLOW_LOAD_LENGTH)
-  #define FILAMENT_CHANGE_SLOW_LOAD_LENGTH 0
+/**
+ * Advanced Pause - Filament Change
+ */
+#if ENABLED(ADVANCED_PAUSE_FEATURE)
+  #if HAS_LCD_MENU || BOTH(EMERGENCY_PARSER, HOST_PROMPT_SUPPORT)
+    #define M600_PURGE_MORE_RESUMABLE 1
+  #endif
+  #ifndef FILAMENT_CHANGE_SLOW_LOAD_LENGTH
+    #define FILAMENT_CHANGE_SLOW_LOAD_LENGTH 0
+  #endif
 #endif
 
 #if HAS_MULTI_EXTRUDER && !defined(TOOLCHANGE_FS_EXTRA_PRIME)