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- Web UI: grey out stale results while a search runs and cancel superseded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>

database/migrations/1768620765070_readable_name_more_shapes.ts

@@ -0,0 +1,43 @@
+import { BaseSchema } from '@adonisjs/lucid/schema'
+
+/**
+ * is_readable_name(): also hex with a Unix time, UUIDs, digit-only names
+ * (and rclone's "83111763 n"), lowercase base32/36 tokens and short tokens
+ * with capitals all over. The same rules as looksRandom() in ArchiveService.
+ */
+export default class extends BaseSchema {
+  async up() {
+    this.defer(async (db) => {
+      await db.rawQuery(`
+        CREATE OR REPLACE FUNCTION is_readable_name(name text) RETURNS boolean IMMUTABLE LANGUAGE sql AS $$
+          WITH s AS (SELECT regexp_replace(name_stem(name), '\\.[A-Za-z0-9]{1,4}$', '') AS stem)
+          SELECT name IS NOT NULL AND NOT (
+            (stem ~ '^[A-Za-z0-9]{16,}$' AND stem ~ '[a-z]' AND stem ~ '[A-Z]'
+              AND (stem ~ '\\d' OR length(regexp_replace(stem, '[^A-Z]', '', 'g')) >= 6))
+            OR stem ~* '^[0-9a-f]{16,}$'
+            OR stem ~* '^[0-9a-f]{16,}\\.\\d{9,}$'
+            OR stem ~* '^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$'
+            OR stem ~ '^\\d{6,}( n){0,1}$'
+            OR (stem ~ '^[a-z0-9]{12,}$' AND length(regexp_replace(stem, '\\D', '', 'g')) >= 2
+                AND length(regexp_replace(stem, '[^a-z]', '', 'g')) >= 4)
+            OR (stem ~ '^[A-Za-z0-9]{8,15}$' AND stem ~ '\\d' AND stem ~ '[a-z]'
+                AND length(regexp_replace(substr(stem, 2), '[^A-Z]', '', 'g')) >= 3))
+          FROM s
+        $$`)
+    })
+  }
+
+  async down() {
+    this.defer(async (db) => {
+      await db.rawQuery(`
+        CREATE OR REPLACE FUNCTION is_readable_name(name text) RETURNS boolean IMMUTABLE LANGUAGE sql AS $$
+          WITH s AS (SELECT regexp_replace(name_stem(name), '\\.[A-Za-z0-9]{1,4}$', '') AS stem)
+          SELECT name IS NOT NULL AND NOT (
+            (stem ~ '^[A-Za-z0-9]{16,}$' AND stem ~ '[a-z]' AND stem ~ '[A-Z]'
+              AND (stem ~ '\\d' OR length(regexp_replace(stem, '[^A-Z]', '', 'g')) >= 6))
+            OR stem ~* '^[0-9a-f]{16,}$')
+          FROM s
+        $$`)
+    })
+  }
+}