fix: Add missing Ollama Cloud models and get_ollama_auth_headers

- Added Ollama Cloud models to get_predefined_model_categories()
- Added get_ollama_auth_headers() function to util.py
- Added Ollama Cloud to category_to_provider mapping
- Imported get_ollama_auth_headers in model.py

This fixes the issue where predefined models weren't showing in /model-show.

src/cai/repl/commands/model.py

@@ -12,7 +12,7 @@ import requests  # pylint: disable=import-error
 from rich.console import Console  # pylint: disable=import-error
 from rich.table import Table  # pylint: disable=import-error
 from rich.panel import Panel  # pylint: disable=import-error
-from cai.util import get_ollama_api_base, COST_TRACKER
+from cai.util import get_ollama_api_base, get_ollama_auth_headers, COST_TRACKER
 from cai.repl.commands.base import Command, register_command
 
 console = Console()
@@ -99,6 +99,32 @@ def get_predefined_model_categories() -> Dict[str, List[Dict[str, str]]]:
                 "name": "deepseek-r1",
                 "description": "DeepSeek's specialized reasoning model"
             }
+        ],
+        "Ollama Cloud": [
+            {
+                "name": "ollama_cloud/gpt-oss:120b",
+                "description": (
+                    "Ollama Cloud - Large 120B parameter model (no GPU required)"
+                )
+            },
+            {
+                "name": "ollama_cloud/llama3.3:70b",
+                "description": (
+                    "Ollama Cloud - Llama 3.3 70B model (no GPU required)"
+                )
+            },
+            {
+                "name": "ollama_cloud/qwen2.5:72b",
+                "description": (
+                    "Ollama Cloud - Qwen 2.5 72B model (no GPU required)"
+                )
+            },
+            {
+                "name": "ollama_cloud/deepseek-v3:671b",
+                "description": (
+                    "Ollama Cloud - DeepSeek V3 671B model (no GPU required)"
+                )
+            }
         ]
     }
 
@@ -117,7 +143,8 @@ def get_all_predefined_models() -> List[Dict[str, Any]]:
         "Alias": "OpenAI",  # Alias models use OpenAI as base
         "Anthropic Claude": "Anthropic",
         "OpenAI": "OpenAI", 
-        "DeepSeek": "DeepSeek"
+        "DeepSeek": "DeepSeek",
+        "Ollama Cloud": "Ollama Cloud"
     }
     
     for category, models in model_categories.items():

src/cai/util.py

@@ -764,6 +764,18 @@ def get_ollama_api_base():
     return "http://localhost:8000/v1"
 
 
+def get_ollama_auth_headers():
+    """Get authentication headers for Ollama Cloud if API key is set.
+    
+    Returns:
+        Dictionary with Authorization header if API key exists, empty dict otherwise
+    """
+    api_key = os.getenv("OLLAMA_API_KEY") or os.getenv("OPENAI_API_KEY")
+    if api_key:
+        return {"Authorization": f"Bearer {api_key}"}
+    return {}
+
+
 def load_prompt_template(template_path):
     """
     Load a prompt template from the package resources.