Add Docker support and refactor prompt/queue internals

- Add Dockerfile, docker-compose.yml, .dockerignore for containerised deployment
- Extract _resolve_character(), _ensure_character_fields(), _append_background() helpers to eliminate repeated inline character-field injection and background-tag patterns across all secondary-category generate routes
- Add _IDENTITY_KEYS / _WARDROBE_KEYS constants
- Fix build_extras_prompt() bug: detailer prompt (a list) was being appended as a single item instead of extended
- Replace all per-route _finalize closures with _make_finalize() factory, reducing duplication across 10 generate routes
- Add _prune_job_history() called each worker loop iteration to prevent unbounded memory growth
- Remove 10 orphaned legacy finalize_generation HTTP routes and check_status route (superseded by job queue API since job-queue branch)
- Remove one-time migration scripts (migrate_actions, migrate_detailers, migrate_lora_weight_range, migrate_wardrobe)
- Update CLAUDE.md and README.md to document new helpers, queue architecture, and Docker deployment

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

README.md

@@ -39,6 +39,20 @@ A local web-based GUI for managing character profiles (JSON) and generating cons
 
 ## Setup & Installation
 
+### Option A — Docker (recommended)
+
+1. **Clone the repository.**
+2. Edit `docker-compose.yml` if needed:
+   - Set `COMFYUI_URL` to your ComfyUI host/port.
+   - Adjust the `/Volumes/ImageModels` volume path to your model directory. If you're on Docker Desktop, add the path under **Settings → Resources → File Sharing** first.
+3. **Start services:**
+   ```bash
+   docker compose up -d
+   ```
+   The app will be available at `http://localhost:5782`.
+
+### Option B — Local (development)
+
 1. **Clone the repository** to your local machine.
 2. **Configure Paths**: Open `app.py` and update the following variables to match your system:
    ```python