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/multiple_fellatio_illustrious_v1_0.json

@@ -2,33 +2,32 @@
   "action_id": "multiple_fellatio_illustrious_v1_0",
   "action_name": "Multiple Fellatio Illustrious V1 0",
   "action": {
-    "full_body": "multiple views, kneeling or sitting position, flanked by two partners, maintaining balance while engaging multiple subjects",
-    "head": "mouth wide open, jaw stretched, head tilted back or neutral, heavily blushing face, messy hair",
-    "eyes": "rolled back (ahegao), heart-shaped pupils, or crossed eyes, streaming tears",
-    "arms": "raised to hold partners or resting on their legs",
-    "hands": "stroking shafts, guiding penises towards mouth, or resting on partners' thighs",
-    "torso": "chest pushed forward, leaning in towards the action",
-    "pelvis": "hips settled on heels or slightly raised in a kneeling stance",
-    "legs": "kneeling, shins flat against the surface, knees spread apart",
-    "feet": "toes curled or resting flat",
-    "additional": "saliva trails, double fellatio, penis in mouth, penis on face, cum on face, high motion lines, explicit sexual activity"
-  },
-  "participants": {
-    "solo_focus": "true",
-    "orientation": "MF"
+    "full_body": "cooperative_fellatio, group_sex, multiple_girls",
+    "head": "open_mouth, tongue_out, licking",
+    "eyes": "upward_gaze, looking_at_penis",
+    "arms": "holding_penis",
+    "hands": "on_penis",
+    "torso": "leaning_forward",
+    "pelvis": "kneeling",
+    "legs": "kneeling",
+    "feet": "toes_curled",
+    "additional": "pov, saliva, penile_stimulation"
   },
   "lora": {
     "lora_name": "Illustrious/Poses/multiple fellatio_illustrious_V1.0.safetensors",
-    "lora_weight": 1.0,
-    "lora_triggers": "multiple fellatio_illustrious_V1.0"
+    "lora_weight": 0.7,
+    "lora_triggers": "multiple fellatio, cooperative fellatio, fellatio, oral, group sex, licking, pov"
   },
   "tags": [
-    "multiple fellatio",
-    "double fellatio",
-    "oral sex",
-    "kneeling",
-    "group sex",
-    "ahegao",
-    "saliva"
+    "cooperative_fellatio",
+    "fellatio",
+    "group_sex",
+    "oral",
+    "licking",
+    "pov",
+    "multiple_girls",
+    "penis",
+    "1boy",
+    "kneeling"
   ]
 }