Improve Power-Loss Recovery (#19540)

Marlin/src/feature/powerloss.h

@@ -107,6 +107,12 @@ typedef struct {
   // Job elapsed time
   millis_t print_job_elapsed;
 
+  // Misc. Marlin flags
+  struct {
+    bool dryrun:1;                // M111 S8
+    bool allow_cold_extrusion:1;  // M302 P1
+  } flag;
+
   uint8_t valid_foot;
 
   bool valid() { return valid_head && valid_head == valid_foot; }
@@ -173,7 +179,10 @@ class PrintJobRecovery {
       }
     #endif
 
-    static inline bool valid() { return info.valid(); }
+    // The referenced file exists
+    static inline bool interrupted_file_exists() { return card.fileExists(info.sd_filename); }
+
+    static inline bool valid() { return info.valid() && interrupted_file_exists(); }
 
     #if ENABLED(DEBUG_POWER_LOSS_RECOVERY)
       static void debug(PGM_P const prefix);