fix: count core copies under their own category

The second pass, the archive-prefix pass and the agnostic scan built
extras without source_name or source_path, so verify found no gap report
entry for them and counted game data such as hiscore.dat as core files.
Every extra now carries its entry's category and key, and verify reads
the category from the extra the builder places.

scripts/packextras.py

@@ -215,7 +215,7 @@ def hidden_extras(
     placed: set[str] | None = None,
     report: list[dict] | None = None,
     resolver: ExtraResolver | None = None,
-    placed_by: dict[str, tuple[str, str, str]] | None = None,
+    placed_kind: dict[str, str] | None = None,
 ) -> dict[tuple[str, str, str], str]:
     """Report entries the builder holds and still leaves out, with the reason.
 
@@ -231,8 +231,10 @@ def hidden_extras(
     file left out. ``shipped`` maps the full destination of each platform
     file the pack carries to its local copy, or to None for a slot it keeps
     without one (user_provided, external). ``placed``, when given,
-    receives the full destination of each held extra the pack carries.
-    ``resolver`` is the builder's lookup. An extra it cannot resolve is
+    receives the full destination of each held extra the pack carries, and
+    ``placed_kind`` its category, carried by the extra itself: the second
+    pass, the archive-prefix pass and the agnostic scan copy files no gap
+    report entry names. ``resolver`` is the builder's lookup. An extra it cannot resolve is
     skipped and takes no path, as the builder skips it.
     """
     from packpaths import _register_path, placement_block
@@ -288,11 +290,8 @@ def hidden_extras(
             lower.add(full.lower())
         if placed is not None and local:
             placed.add(full)
-        if placed_by is not None and local:
-            placed_by[full] = (
-                fe.get("source_emulator", ""), fe.get("source_name", ""),
-                fe.get("source_path", ""),
-            )
+        if placed_kind is not None and local:
+            placed_kind[full] = fe.get("category", "bios")
     return hidden
 
 
@@ -469,6 +468,9 @@ def _agnostic_scan_extras(
                         "hle_fallback": False,
                         "source_emulator": profile.get("emulator", emu_name),
                         "source_profile": emu_name,
+                        "source_name": fname,
+                        "source_path": f.get("path") or "",
+                        "category": f.get("category", "bios"),
                         "source_system": f.get("system"),
                         "source_systems": list(profile.get("systems", [])),
                         "region": f.get("region"),
@@ -622,6 +624,9 @@ def _companion_extras(
             "hle_fallback": False,
             "source_emulator": profile.get("emulator", emu_name),
             "source_profile": emu_name,
+            "source_name": seed.get("name", ""),
+            "source_path": seed.get("path") or "",
+            "category": seed.get("category", "bios"),
             "source_system": seed.get("system"),
             "source_systems": list(profile.get("systems", [])),
             "region": seed.get("region"),
@@ -734,6 +739,10 @@ def _archive_prefix_extras(
                 "hle_fallback": False,
                 "source_emulator": profile.get("emulator", emu_name),
                 "source_profile": emu_name,
+                # Keyed as the gap report keys an archive: name and path alike.
+                "source_name": archive_name,
+                "source_path": archive_name,
+                "category": archive_entry.get("category", "bios"),
                 "source_system": archive_entry.get("system"),
                 "source_systems": list(profile.get("systems", [])),
                 "region": archive_entry.get("region"),
@@ -1032,6 +1041,10 @@ def _collect_emulator_extras(
                     "hle_fallback": f.get("hle_fallback", False),
                     "source_emulator": profile.get("emulator", emu_name),
                     "source_profile": emu_name,
+                    # The key the gap report gives the same entry.
+                    "source_name": fname,
+                    "source_path": raw,
+                    "category": f.get("category", "bios"),
                     "source_system": f.get("system"),
                     "source_systems": list(profile.get("systems", [])),
                     "region": f.get("region"),
@@ -1161,6 +1174,7 @@ def _report_extra(u: dict, name: str, dest: str) -> dict:
         # the wrong regional variant from the report.
         "source_name": u.get("name", ""),
         "source_path": u.get("path") or "",
+        "category": u.get("category", "bios"),
         "source_system": u.get("system"),
         "source_systems": u.get("systems", []),
         "region": u.get("region"),