Spotnet import, header backfill, staging and counter grouping, faster search

Spotnet (CONCEPT D29):
- Index free.pt fully and import spots with their descriptions, categories
  and NZBs; a spot renames its release, since Spotnet names are more
  trustworthy than names derived from subjects.
- Find passwords in spot descriptions too, and tell "needs a password we
  have" from "needs a password we don't have".

Content inspection:
- List the contents of 7z (.7z.001) archives, SFV sets, nicovideo uploads
  and other archive-like files; mark yEncBin .bin containers as encrypted.
- Take real names from yEnc headers for randomly named files, and merge
  uploads that were split across posts.

Storage (D31, D32):
- Store segment lists zstd-compressed behind the FileStore accessor.
- group:backfill indexes older headers at low priority and pauses when
  the NVMe or HDD part of the database gets too large.

Grouping (D35, D36):
- Lone header segments wait in staged_segments until a second segment of
  their file arrives, which drops the per-article junk binaries.
- Counter grouping joins random-subject uploads by poster, [i/M] counter,
  part count and day.

Search and maintenance (D33, D34):
- A trigram-indexed search_text column, smaller indexes, estimated stats.
- Passes that clean up nonsense names; weekly index maintenance; GC budgets
  per kind.
- Web UI: grey out stale results while a search runs and cancel superseded
  requests. Count only up to 1,000 matches for the page, which made filter
  clicks take seconds (Newznab keeps the 10,000 cap).

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

public/app.css

@@ -263,6 +263,41 @@ kbd {
   font-size: 13px;
 }
 
+/* While a new search runs, the previous results stay in place but greyed out. */
+.release-list.stale {
+  opacity: 0.4;
+  pointer-events: none;
+  transition: opacity 0.12s ease-out;
+}
+
+.results[aria-busy='true'] .summary::after {
+  content: '';
+  display: block;
+  height: 2px;
+  margin-top: 6px;
+  border-radius: 1px;
+  background: linear-gradient(90deg, transparent, var(--accent), transparent);
+  background-size: 40% 100%;
+  background-repeat: no-repeat;
+  animation: searching 1s linear infinite;
+}
+
+@keyframes searching {
+  from {
+    background-position: -40% 0;
+  }
+  to {
+    background-position: 140% 0;
+  }
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .results[aria-busy='true'] .summary::after {
+    animation: none;
+    background: var(--accent-soft);
+  }
+}
+
 .release-list {
   list-style: none;
   margin: 0;
@@ -563,6 +598,70 @@ kbd {
   color: var(--bad);
 }
 
+.notice-good {
+  background: var(--good-soft);
+  color: var(--good);
+}
+
+.notice .password {
+  padding: 1px 6px;
+  border-radius: 4px;
+  background: var(--surface);
+  color: var(--text);
+  font-family: var(--mono);
+  user-select: all;
+  overflow-wrap: anywhere;
+}
+
+.spot {
+  display: flex;
+  gap: 16px;
+  align-items: flex-start;
+}
+
+.spot-image {
+  flex: none;
+  width: 140px;
+  height: auto;
+  border-radius: 6px;
+  background: var(--surface-2);
+}
+
+.spot-body {
+  flex: 1;
+  min-width: 0;
+}
+
+.spot-body .facts {
+  margin-bottom: 14px;
+}
+
+.spot-description {
+  font-size: 13.5px;
+  line-height: 1.55;
+  overflow-wrap: anywhere;
+}
+
+.spot-description a,
+.spot-links a {
+  color: var(--accent);
+}
+
+.spot-links {
+  display: flex;
+  flex-direction: column;
+  gap: 4px;
+  margin-top: 12px;
+  font-size: 13px;
+  overflow-wrap: anywhere;
+}
+
+@media (max-width: 560px) {
+  .spot {
+    flex-direction: column;
+  }
+}
+
 .notice-warn {
   background: var(--warn-soft);
   color: var(--warn);