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/goblins_burrow_il_nai_py.json

@@ -2,37 +2,37 @@
   "action_id": "goblins_burrow_il_nai_py",
   "action_name": "Goblins Burrow Il Nai Py",
   "action": {
-    "full_body": "size difference, character crouching low to the ground in a deep, feral squat or crawling position",
-    "head": "tilted upward or hunched low, often with a mischievous or feral expression, tongue out",
-    "eyes": "wide open, dilated pupils, looking up at viewer",
-    "arms": "reaching towards the ground between legs or resting on knees, elbows bent",
-    "hands": "palms on the floor or clawing at the ground, fingers spread",
-    "torso": "leaning forward sharply, hunched back or arched depending on angle, compact posture",
-    "pelvis": "lowered close to the heels, anterior pelvic tilt",
-    "legs": "knees bent deeply and spread wide apart, thighs pressing against ribs or opened outward",
-    "feet": "resting on toes with heels raised or flat on ground, indicating readiness to pounce",
-    "additional": "dynamic angle, low perspective, emphasis on hips and flexibility"
-  },
-  "participants": {
-    "solo_focus": "true",
-    "orientation": "MF"
+    "full_body": "standing_sex, carrying, interspecies, size_difference",
+    "head": "blush, sweat, ahegao",
+    "eyes": "closed_eyes, half-closed_eyes",
+    "arms": "embracing, arms_around_neck",
+    "hands": "clinging",
+    "torso": "large_breasts, nipples, nude",
+    "pelvis": "sex, cum_in_pussy, vaginal_penetration",
+    "legs": "spread_legs, wrapped_around",
+    "feet": "barefoot",
+    "additional": "cave, outdoors, torn_clothes, peephole"
   },
   "lora": {
     "lora_name": "Illustrious/Poses/Goblins burrow-IL_NAI_PY.safetensors",
-    "lora_weight": 1.0,
-    "lora_triggers": "Goblins burrow-IL_NAI_PY"
+    "lora_weight": 0.6,
+    "lora_triggers": "goblin, burrow, frog embrace position"
   },
   "tags": [
-    "squatting",
-    "crouching",
-    "goblin mode",
-    "feral",
-    "spread legs",
-    "knees apart",
-    "on toes",
-    "all fours",
-    "looking up",
-    "shortstack",
-    "hunched over"
+    "goblin",
+    "standing_sex",
+    "size_difference",
+    "interspecies",
+    "spread_legs",
+    "carrying",
+    "cave",
+    "outdoors",
+    "sweat",
+    "blush",
+    "torn_clothes",
+    "cum",
+    "peephole",
+    "1girl",
+    "1boy"
   ]
 }