Add Checkpoints Gallery with per-checkpoint generation settings

- New Checkpoint model (slug, name, checkpoint_path, data JSON, image_path)
- sync_checkpoints() loads metadata from data/checkpoints/*.json and falls
  back to template defaults for models without a JSON file
- _apply_checkpoint_settings() applies per-checkpoint steps, CFG, sampler,
  base positive/negative prompts, and VAE (with dynamic VAELoader node
  injection for non-integrated VAEs) to the ComfyUI workflow
- Bulk Create from Checkpoints: scans Illustrious/Noob model directories,
  reads matching HTML files, uses LLM to populate metadata, falls back to
  template defaults when no HTML is present
- Gallery index with batch cover generation and WebSocket progress bar
- Detail page showing Generation Settings and Base Prompts cards
- Checkpoints nav link added to layout
- New data/prompts/checkpoint_system.txt LLM system prompt
- Updated README with all current galleries and file structure
- Also includes accumulated action/scene JSON updates, new actions, and
  other template/generator improvements from prior sessions

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

data/actions/amateur_pov_filming.json

@@ -2,33 +2,32 @@
   "action_id": "amateur_pov_filming",
   "action_name": "Amateur Pov Filming",
   "action": {
-    "full_body": "POV shot, subject positioned close to the lens, selfie composition or handheld camera style",
-    "head": "facing the camera directly, slightly tilted or chin tucked, candid expression",
-    "eyes": "looking directly at viewer, intense eye contact",
-    "arms": "one or both arms raised towards the viewer holding the capturing device",
-    "hands": "holding smartphone, clutching camera, fingers visible on device edges",
-    "torso": "upper body visible, facing forward, close proximity",
-    "pelvis": "obscured or out of frame",
-    "legs": "out of frame",
-    "feet": "out of frame",
-    "additional": "phone screen, camera interface, amateur footage quality, blurry background, indoor lighting, candid atmosphere"
-  },
-  "participants": {
-    "solo_focus": "true",
-    "orientation": "MF"
+    "full_body": "selfie pose, standing or sitting, facing viewer or mirror",
+    "head": "looking_at_viewer, blush, maybe open mouth or shy expression",
+    "eyes": "looking_at_viewer, contact with camera",
+    "arms": "raised to hold phone or camera",
+    "hands": "holding_phone, holding_id_card, or adjusting clothes",
+    "torso": "upper body in frame, breasts, nipples",
+    "pelvis": "hips visible if full body mirror selfie",
+    "legs": "standing or sitting",
+    "feet": "barefoot if visible",
+    "additional": "phone recording interface, smartphone, mirror, amateur aesthetic"
   },
   "lora": {
     "lora_name": "Illustrious/Poses/Amateur_POV_Filming.safetensors",
     "lora_weight": 1.0,
-    "lora_triggers": "Amateur_POV_Filming"
+    "lora_triggers": "Homemade_PornV1, recording, pov, prostitution"
   },
   "tags": [
+    "recording",
     "pov",
     "selfie",
-    "holding phone",
-    "amateur",
-    "candid",
-    "recording",
-    "close-up"
+    "holding_phone",
+    "smartphone",
+    "mirror_selfie",
+    "holding_id_card",
+    "looking_at_viewer",
+    "prostitution",
+    "indoors"
   ]
 }