fix: a game build is recognised before the archive integrity test, so re-extract no longer stalls on it

The archive probe read and checksummed every member before the importer
looked at what the archive held. For a multi-gigabyte game build that is
minutes of work on a file that is kept whole and never extracted, and it
held a re-extract chunk far past its time budget.

- The importer checks the archive's directory for a software build first,
  for the outer archive and for one nested inside an art pack, and only
  probes archives it may extract.
- The probe rejects an archive over the size cap from its directory totals,
  before the integrity test decompresses anything.
- Re-extract logs each archive as it starts and finishes, with its size and
  how long it took, so an archive that stalls a chunk is named in the log.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_importer_archive.py

@@ -305,3 +305,24 @@ def test_a_game_build_inside_an_art_pack_is_skipped_and_the_art_imported(importe
     assert r.status == "imported"
     assert len(r.member_image_ids) == 1
     assert importer.session.execute(select(func.count()).select_from(ImageRecord)).scalar_one() == 1
+
+
+def test_a_game_build_is_recognised_before_the_integrity_test(
+    importer, import_layout, monkeypatch,
+):
+    """A multi-gigabyte build would spend minutes in the probe's read-everything
+    test, only to be kept whole anyway, so its directory decides first."""
+    from backend.app.utils import safe_probe
+
+    def _no_probe(_path, **_kw):
+        raise AssertionError("a software build went through the archive probe")
+    monkeypatch.setattr(safe_probe, "probe_archive", _no_probe)
+    import_root, _ = import_layout
+    arc = import_root / "Bob" / "MyGame-2.0-pc.zip"
+    arc.parent.mkdir(parents=True, exist_ok=True)
+    with zipfile.ZipFile(arc, "w") as zf:
+        zf.writestr("MyGame/MyGame.exe", b"MZ")
+        zf.writestr("MyGame/game/images/cg01.jpg", _split_bytes("v"))
+
+    assert importer.import_one(arc).status == "attached"
+    assert importer.session.execute(select(func.count()).select_from(ImageRecord)).scalar_one() == 0