fix: escape LIKE wildcards in user-search ILIKE queries

A `%` or `_` in a search term silently acted as a LIKE wildcard rather than
matching literally (`50%` matched everything, `a_b` matched `axb`). Not
injection — terms are bound — but a search-correctness bug across every
user-facing ILIKE site.

- repo::escape_like: shared pub(crate) escaper (promoted from page_tag), unit-tested.
- Trigram-entangled sites (manga, tag, author) append a separate escaped param
  used only by the ILIKE branch; the trigram/similarity branches keep the raw term.
- Pattern-built sites (admin manga list, admin users, analysis coverage + history,
  crawler search incl. JSONB payload title) escape inside format!("%{}%", ..) and
  pair each ILIKE with ESCAPE '\'.

Tests: escape_like unit tests + integration tests on public manga search, author
autocomplete, and admin user search proving `_` matches literally.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/package.json

@@ -1,6 +1,6 @@
 {
   "name": "mangalord-frontend",
-  "version": "0.128.5",
+  "version": "0.128.6",
   "private": true,
   "type": "module",
   "scripts": {