fix(perception): resolve UNKNOWN screen classification on explore grid and fix LLM fallback API

1. Added a robust structural heuristic for EXPLORE_GRID that looks for 'action_bar_search_edit_text' alongside 'search_tab', eliminating the reliance on the flaky 'selected' attribute.
2. Fixed a critical bug in the LLM semantic fallback where it was incorrectly querying the '/api/chat' endpoint using an '/api/generate' payload format, causing silent 400 Bad Request failures.
3. Corrected the fallback model assignment to use 'ai_model' (e.g. qwen3.5) instead of 'ai_embedding_model' (which incorrectly attempted to use nomic-embed-text or llama3 for chat completion).

GramAddict/core/perception/screen_identity.py

@@ -219,6 +219,8 @@ class ScreenIdentity:
             return ScreenType.REELS_FEED
         if selected_tab == "search_tab":
             return ScreenType.EXPLORE_GRID
+        if "action_bar_search_edit_text" in ids and "search_tab" in ids:
+            return ScreenType.EXPLORE_GRID
         if selected_tab == "profile_tab":
             return ScreenType.OWN_PROFILE
         if selected_tab == "direct_tab":
@@ -232,11 +234,11 @@ class ScreenIdentity:
 
         cfg = Config()
         url = (
-            getattr(cfg.args, "ai_embedding_url", "http://localhost:11434/api/chat")
+            getattr(cfg.args, "ai_model_url", "http://localhost:11434/api/generate")
             if hasattr(cfg, "args")
-            else "http://localhost:11434/api/chat"
+            else "http://localhost:11434/api/generate"
         )
-        model = getattr(cfg.args, "ai_embedding_model", "llama3") if hasattr(cfg, "args") else "llama3"
+        model = getattr(cfg.args, "ai_model", "qwen3.5:latest") if hasattr(cfg, "args") else "qwen3.5:latest"
 
         layout_context = (
             f"Selected Tab: {selected_tab}\nResource IDs: {list(ids)}\nVisible Texts context: {texts[:10]}\n"