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>

templates/partials/library_toolbar.html

@@ -0,0 +1,70 @@
+{% macro library_toolbar(title, category,
+                          create_url=none, create_label=none,
+                          has_batch_gen=true, has_regen_all=true,
+                          has_lora_create=false, bulk_create_url=none,
+                          has_tags=true, regen_tags_category=none,
+                          rescan_url=none,
+                          get_missing_url=none, clear_covers_url=none,
+                          generate_url_pattern=none) %}
+<div class="d-flex justify-content-between align-items-center mb-4"
+     data-toolbar-category="{{ category }}"
+     {% if get_missing_url %}data-get-missing-url="{{ get_missing_url }}"{% endif %}
+     {% if clear_covers_url %}data-clear-covers-url="{{ clear_covers_url }}"{% endif %}
+     {% if generate_url_pattern %}data-generate-url="{{ generate_url_pattern }}"{% endif %}
+     {% if regen_tags_category %}data-regen-tags-category="{{ regen_tags_category }}"{% endif %}
+     {% if bulk_create_url %}data-bulk-create-url="{{ bulk_create_url }}"{% endif %}>
+    <h2>{{ title }} Library</h2>
+    <div class="d-flex gap-2 align-items-center">
+        {% if create_url %}
+        <a href="{{ create_url }}" class="btn btn-sm btn-success">+ {{ create_label or title }}</a>
+        {% endif %}
+
+        <div class="dropdown">
+            <button class="btn btn-sm btn-outline-secondary dropdown-toggle" type="button"
+                    data-bs-toggle="dropdown" aria-expanded="false">
+                Actions
+            </button>
+            <ul class="dropdown-menu dropdown-menu-end">
+                {% if has_batch_gen %}
+                <li><button class="dropdown-item" id="batch-generate-btn" data-requires="comfyui">
+                    Generate Missing Covers
+                </button></li>
+                {% endif %}
+                {% if has_regen_all %}
+                <li><button class="dropdown-item text-danger" id="regenerate-all-btn" data-requires="comfyui">
+                    Regenerate All Covers
+                </button></li>
+                {% endif %}
+
+                {% if (has_batch_gen or has_regen_all) and (has_tags or has_lora_create) %}
+                <li><hr class="dropdown-divider"></li>
+                {% endif %}
+
+                {% if has_tags %}
+                <li><button class="dropdown-item" id="regen-tags-all-btn" data-requires="llm">
+                    Regenerate Tags (LLM)
+                </button></li>
+                {% endif %}
+
+                {% if has_lora_create %}
+                <li><button class="dropdown-item" id="bulk-create-btn" data-requires="llm">
+                    Create from LoRAs (LLM)
+                </button></li>
+                <li><button class="dropdown-item text-danger" id="bulk-overwrite-btn" data-requires="llm">
+                    Overwrite All from LoRAs (LLM)
+                </button></li>
+                {% endif %}
+
+                {% if rescan_url %}
+                <li><hr class="dropdown-divider"></li>
+                <li>
+                    <form action="{{ rescan_url }}" method="post" class="d-contents">
+                        <button type="submit" class="dropdown-item">Rescan from Disk</button>
+                    </form>
+                </li>
+                {% endif %}
+            </ul>
+        </div>
+    </div>
+</div>
+{% endmacro %}