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/hikage_senran_kagura.json

@@ -0,0 +1,66 @@
+{
+  "character_id": "hikage_senran_kagura",
+  "character_name": "Hikage - Senran Kagura",
+  "identity": {
+    "base_specs": "1girl, mature_female, large_breasts, athletic_build, pale_skin",
+    "hair": "green_hair, short_hair, spiked_hair",
+    "eyes": "yellow_eyes, slit_pupils",
+    "hands": "fingernails",
+    "arms": "arm_belt, tattoo",
+    "torso": "chest_tattoo, stomach_tattoo, navel",
+    "pelvis": "open_fly",
+    "legs": "torn_jeans, leg_belt",
+    "feet": "boots",
+    "extra": "neck_tattoo, snake_print"
+  },
+  "defaults": {
+    "expression": "stoic",
+    "pose": "standing",
+    "scene": ""
+  },
+  "wardrobe": {
+    "full_body": "torn_clothes",
+    "headwear": "",
+    "top": "yellow_shirt, crop_top, torn_clothes",
+    "bottom": "torn_jeans, open_fly, loose_belt",
+    "legwear": "",
+    "footwear": "boots",
+    "hands": "arm_belt",
+    "accessories": "leg_belt"
+  },
+  "styles": {
+    "aesthetic": "anime, video_game_character",
+    "primary_color": "yellow",
+    "secondary_color": "green",
+    "tertiary_color": "blue"
+  },
+  "lora": {
+    "lora_name": "Illustrious/Looks/SK_Hikage_IL.safetensors",
+    "lora_weight": 0.8,
+    "lora_triggers": "Hikage_IL, Hikage_Shinobi",
+    "lora_weight_min": 0.8,
+    "lora_weight_max": 0.8
+  },
+  "tags": [
+    "hikage_(senran_kagura)",
+    "green_hair",
+    "short_hair",
+    "yellow_eyes",
+    "slit_pupils",
+    "large_breasts",
+    "neck_tattoo",
+    "chest_tattoo",
+    "stomach_tattoo",
+    "yellow_shirt",
+    "crop_top",
+    "torn_clothes",
+    "torn_jeans",
+    "open_fly",
+    "loose_belt",
+    "snake_print",
+    "arm_belt",
+    "leg_belt",
+    "anime",
+    "video_game_character"
+  ]
+}