Add semantic tagging, search, favourite/NSFW filtering, and LLM job queue

Replaces old list-format tags (which duplicated prompt content) with structured
dict tags per category (origin_series, outfit_type, participants, style_type,
scene_type, etc.). Tags are now purely organizational metadata — removed from
the prompt pipeline entirely.

Adds is_favourite and is_nsfw columns to all 8 resource models. Favourite is
DB-only (user preference); NSFW is mirrored in JSON tags for rescan persistence.
All library pages get filter controls and favourites-first sorting.

Introduces a parallel LLM job queue (_enqueue_task + _llm_queue_worker) for
background tag regeneration, with the same status polling UI as ComfyUI jobs.
Fixes call_llm() to use has_request_context() fallback for background threads.

Adds global search (/search) across resources and gallery images, with navbar
search bar. Adds gallery image sidecar JSON for per-image favourite/NSFW metadata.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

routes/__init__.py

@@ -18,6 +18,8 @@ def register_routes(app):
     from routes import strengths
     from routes import transfer
     from routes import api
+    from routes import regenerate
+    from routes import search
 
     queue_api.register_routes(app)
     settings.register_routes(app)
@@ -37,3 +39,5 @@ def register_routes(app):
     strengths.register_routes(app)
     transfer.register_routes(app)
     api.register_routes(app)
+    regenerate.register_routes(app)
+    search.register_routes(app)