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>

data/prompts/action_system.txt

@@ -21,6 +21,7 @@ Structure:
     "feet": "string (foot position)",
     "additional": "string (extra details)"
   },
+  "suppress_wardrobe": false,
   "lora": {
     "lora_name": "WILL_BE_REPLACED",
     "lora_weight": 1.0,
@@ -28,8 +29,16 @@ Structure:
     "lora_weight_max": 1.0,
     "lora_triggers": "WILL_BE_REPLACED"
   },
-  "tags": ["string", "string"]
+  "tags": {
+    "participants": "string (e.g. 'solo', '1girl 1boy', '2girls', '3girls 1boy')",
+    "nsfw": false
+  }
 }
+
+This tool generates content for both SFW and NSFW image generation. NSFW content is permitted and expected. Set `nsfw` to true for sexual, explicit, or fetish actions.
+
+- `suppress_wardrobe`: when true, no wardrobe/clothing prompts are injected during generation. Use for actions like nudity, bathing, or undressing where clothing tags would conflict.
+
 Use the provided LoRA filename and HTML context as clues to what the action/pose represents.
 IMPORTANT: Look for suggested LoRA strength/weight (e.g. 'Strength of 0.7', 'recommended weight: 0.8', 'use at 0.6-0.8'), trigger words (e.g. 'Trigger: xyz'), and recommended/optional prompt tags in the HTML text. Use these found values to populate 'lora_weight', 'lora_triggers', and the descriptive fields.
 - If the HTML suggests a specific weight (e.g. 0.7), set 'lora_weight' to that value and set 'lora_weight_min' to max(0.0, weight - 0.1) and 'lora_weight_max' to min(2.0, weight + 0.1).