fix(i18n): rename Ollama keys to LiteLLM in all language files

The dashboard code references dashboard.litellm_settings,
dashboard.litellm_url, dashboard.litellm_url_placeholder, and
dashboard.litellm_status but the i18n JSON files still had the
old Ollama key names. Also updates hint/placeholder text to
reference LITELLM_URL / LITELLM_MODEL env vars.

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

assets/i18n/en.json

@@ -58,15 +58,15 @@
     "title": "Dashboard",
     "subtitle": "AI news and updates",
     "topic_placeholder": "Topic name...",
-    "ollama_settings": "Ollama Settings",
-    "settings_hint": "Leave empty to use OLLAMA_URL / OLLAMA_MODEL from .env",
-    "ollama_url": "Ollama URL",
-    "ollama_url_placeholder": "Uses OLLAMA_URL from .env",
+    "litellm_settings": "LiteLLM Settings",
+    "settings_hint": "Leave empty to use LITELLM_URL / LITELLM_MODEL from .env",
+    "litellm_url": "LiteLLM URL",
+    "litellm_url_placeholder": "Uses LITELLM_URL from .env",
     "model": "Model",
-    "model_placeholder": "Uses OLLAMA_MODEL from .env",
+    "model_placeholder": "Uses LITELLM_MODEL from .env",
     "searching": "Searching...",
     "search_failed": "Search failed: {e}",
-    "ollama_status": "Ollama Status",
+    "litellm_status": "LiteLLM Status",
     "trending": "Trending",
     "recent_searches": "Recent Searches"
   },