feat: record files a launcher never opens

unread_on names the platforms whose launcher points the emulator at other files. RetroBat writes absolute BIOS paths into standalone BlastEm's config, so the default names were reported as required and missing there. Such an entry leaves that platform's gap report and pack, and its emulator page says where it is never opened.

scripts/verify.py

@@ -97,6 +97,7 @@ from validation import (
     deliverable,
     filter_files_by_mode,
     installed_with_emulator,
+    unread_on,
     outside_gap_scope,
 )
 
@@ -540,7 +541,7 @@ def find_undeclared_files(
                     f.get("variant_group"),
                     region_key,
                 )
-                if not fname:
+                if not fname or unread_on(f, config.get("_key", "")):
                     continue
                 first = reported.get(seen_key)
                 duplicate = seen_key in seen_files