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/tongue_lick__press.json

@@ -2,36 +2,30 @@
   "action_id": "tongue_lick__press",
   "action_name": "Tongue Lick Press",
   "action": {
-    "full_body": "close-up or upper body shot, character leaning intimately towards the viewer or a transparent surface",
-    "head": "face pushed forward, chin tilted slightly up, facial muscles relaxed but focused on the mouth",
-    "eyes": "looking at viewer, half-closed or crossed eyes (ahegao style), intense gaze",
-    "arms": "raised to frame the face or resting on the surface being licked",
-    "hands": "palms potentially pressed against the screen/glass, fingers splayed",
-    "torso": "leaning forward, chest pressed slightly if close to surface",
-    "pelvis": "n/a (usually out of frame)",
-    "legs": "n/a (usually out of frame)",
-    "feet": "n/a (usually out of frame)",
-    "additional": "tongue pressed flat against the screen/glass, saliva strings, visible moisture on tongue, breath condensation"
-  },
-  "participants": {
-    "solo_focus": "true",
-    "orientation": "MF"
+    "full_body": "close-up, side view, intimate distance",
+    "head": "open_mouth, tongue_out, saliva, drooling, head_tilt",
+    "eyes": "half-closed_eyes, lustful",
+    "arms": "arms_around_neck",
+    "hands": "holding_head, cup_face",
+    "torso": "upper_body",
+    "pelvis": "n/a",
+    "legs": "n/a",
+    "feet": "n/a",
+    "additional": "licking, french_kiss, wet"
   },
   "lora": {
     "lora_name": "Illustrious/Poses/Tongue_Lick__Press.safetensors",
-    "lora_weight": 1.0,
-    "lora_triggers": "Tongue_Lick__Press"
+    "lora_weight": 0.6,
+    "lora_triggers": "tongue lick, tongue press"
   },
   "tags": [
-    "tongue",
     "tongue_out",
     "licking",
-    "tongue_press",
-    "against_glass",
-    "saliva",
     "open_mouth",
+    "saliva",
+    "drooling",
+    "french_kiss",
     "close-up",
-    "pov",
-    "wet_tongue"
+    "from_side"
   ]
 }