feat(recommendations): content-based "Recommended for you" endpoint

Add GET /me/recommendations: rank mangas by weighted tag overlap with the
user's taste — explicit like +1.0, bookmark +0.5, dislike −1.0 (reaction
overrides bookmark). Per-tag affinities are summed, candidates scored by
their tags' affinity normalized by tag count (anti-tag-stuffing, à la
list_similar), with already-reacted/bookmarked/read mangas excluded and
net-negative candidates dropped (dislike down-ranks, not browse-hides).
Reuses manga_cols/cards_from_rows. Integration tests cover like-driven recs,
dislike down-rank, bookmark half-weight ordering, seen-exclusion, empty
cold-start, and auth.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "mangalord-frontend",
-  "version": "0.107.0",
+  "version": "0.108.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "mangalord-frontend",
-      "version": "0.107.0",
+      "version": "0.108.0",
       "devDependencies": {
         "@lucide/svelte": "^1.16.0",
         "@playwright/test": "^1.48.0",

frontend/package.json

@@ -1,6 +1,6 @@
 {
   "name": "mangalord-frontend",
-  "version": "0.107.0",
+  "version": "0.108.0",
   "private": true,
   "type": "module",
   "scripts": {