fix(download): dispatch archive/non-media in attach_in_place; reshuffle showcase on mount

attach_in_place mirrored only the media flow, so gallery-dl-downloaded
zips/PDFs/audio bounced back as `skipped+invalid_image`, which
download_service counted as an ingest error and flipped runs to
status="error" despite N successful image attaches. Lustria patreon
event #38998 (21 images + 1 OST zip) went red for exactly this reason.

Now attach_in_place dispatches the same way as import_one: archives →
_import_archive (extracts media members, captures archive as
PostAttachment), non-media → _capture_attachment. Download_service
accepts the new `attached` result and treats non-duplicate skips as
soft skips, not ingest errors.

Also: ShowcaseView always loadInitial() on mount, not just when the
store is empty — Pinia persists across navigations and operator wants
a fresh shuffle every time the showcase loads.

backend/app/services/download_service.py

@@ -279,6 +279,21 @@ class DownloadService:
                 for img_id in ids:
                     generate_thumbnail.delay(img_id)
                     tag_and_embed.delay(img_id)
+            elif result.status == "attached":
+                # Non-media or extracted archive captured as PostAttachment
+                # (FC-2d-iii). The canonical copy lives in the attachments
+                # store; the original download path is now redundant —
+                # mirror duplicate_hash cleanup so we don't keep two copies.
+                # Operator-flagged 2026-06-02 (Lustria OST zip).
+                import_summary["attached"] += 1
+                try:
+                    bytes_downloaded += path.stat().st_size  # noqa: ASYNC240
+                except OSError:
+                    pass
+                try:
+                    path.unlink(missing_ok=True)  # noqa: ASYNC240
+                except OSError:
+                    pass
             elif result.status == "skipped" and result.skip_reason and result.skip_reason.value in (
                 "duplicate_hash", "duplicate_phash",
             ):
@@ -287,6 +302,12 @@ class DownloadService:
                     path.unlink(missing_ok=True)  # noqa: ASYNC240
                 except OSError:
                     pass
+            elif result.status == "skipped":
+                # Soft skip (too_small, too_transparent, invalid_image) —
+                # the file just didn't qualify, not a download/ingest
+                # failure. Don't flag the run as error; the file stays
+                # on disk for operator inspection.
+                import_summary["skipped"] += 1
             else:
                 import_summary["errors"] += 1