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/characters/lara_croft_classic.json

@@ -22,7 +22,7 @@
     "default": {
       "full_body": "",
       "headwear": "",
-      "top": "teal tank top,",
+      "top": "teal leotard",
       "bottom": "brown shorts",
       "legwear": "thigh holsters",
       "footwear": "brown combat boots, red laces",
@@ -46,4 +46,4 @@
   "tags": [
     "Tomb Raider"
   ]
-}
+}