Add extra prompts, endless generation, random character default, and small fixes

- Add extra positive/negative prompt textareas to all 9 detail pages with session persistence
- Add Endless generation button to all detail pages (continuous preview generation until stopped)
- Default character selector to "Random Character" on all secondary detail pages
- Fix queue clear endpoint (remove spurious auth check)
- Refactor app.py into routes/ and services/ modules
- Update CLAUDE.md with new architecture documentation
- Various data file updates and cleanup

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

data/scenes/barbie_b3dr00m_i.json

@@ -24,8 +24,8 @@
     "lora_name": "Illustrious/Backgrounds/Barbie_b3dr00m-i.safetensors",
     "lora_weight": 1.0,
     "lora_triggers": "barbie bedroom",
-    "lora_weight_min": 1.0,
-    "lora_weight_max": 1.0
+    "lora_weight_min": 0.4,
+    "lora_weight_max": 0.8
   },
   "tags": [
     "barbie_(franchise)",