fix: AG2 LLMConfig dict API + default utility model matches primary

- roles.py: replace 'with llm_config:' context manager (unsupported in AG2
  v0.12.0) with llm_config= parameter approach
- config.py: default utility_model changed from qwen2.5:7b (often not
  installed) to qwen2.5:14b (same as primary, works out of box)

Tested: specsmith agent plan + specsmith agent run both execute full
Planner→Builder→Verifier pipeline end-to-end with Ollama

Co-Authored-By: Oz <oz-agent@warp.dev>

Author: tbitcs

src/specsmith/agents/config.py

@@ -14,7 +14,7 @@ class AgentConfig:
     """Configuration for the AG2 agent shell."""
 
     primary_model: str = "qwen2.5:14b"
-    utility_model: str = "qwen2.5:7b"
+    utility_model: str = "qwen2.5:14b"  # same as primary; override in scaffold.yml
     ollama_base_url: str = "http://localhost:11434"
     max_iterations: int = 10
     stream: bool = False

src/specsmith/agents/roles.py

@@ -108,13 +108,13 @@ def _git_changed() -> str:
     def _git_branch() -> str:
         return git_branch_info(project_dir=pd)
 
-    with llm_config:
-        agent = ConversableAgent(
-            name="Planner",
-            system_message=PLANNER_PROMPT,
-            human_input_mode="NEVER",
-            functions=[_read_file, _list_tree, _search, _git_status, _git_changed, _git_branch],
-        )
+    agent = ConversableAgent(
+        name="Planner",
+        system_message=PLANNER_PROMPT,
+        human_input_mode="NEVER",
+        llm_config=llm_config,
+        functions=[_read_file, _list_tree, _search, _git_status, _git_changed, _git_branch],
+    )
     return agent
 
 
@@ -150,16 +150,16 @@ def _git_status() -> str:
     def _git_diff() -> str:
         return git_diff(project_dir=pd)
 
-    with llm_config:
-        agent = ConversableAgent(
-            name="Builder",
-            system_message=BUILDER_PROMPT,
-            human_input_mode="NEVER",
-            functions=[
-                _read_file, _write_file, _patch_file, _list_tree,
-                _run_command, _git_status, _git_diff,
-            ],
-        )
+    agent = ConversableAgent(
+        name="Builder",
+        system_message=BUILDER_PROMPT,
+        human_input_mode="NEVER",
+        llm_config=llm_config,
+        functions=[
+            _read_file, _write_file, _patch_file, _list_tree,
+            _run_command, _git_status, _git_diff,
+        ],
+    )
     return agent
 
 
@@ -193,11 +193,11 @@ def _git_status() -> str:
     def _git_diff() -> str:
         return git_diff(project_dir=pd)
 
-    with llm_config:
-        agent = ConversableAgent(
-            name="Verifier",
-            system_message=VERIFIER_PROMPT,
-            human_input_mode="NEVER",
-            functions=[_run_tests, _summarize, _read_file, _run_command, _git_status, _git_diff],
-        )
+    agent = ConversableAgent(
+        name="Verifier",
+        system_message=VERIFIER_PROMPT,
+        human_input_mode="NEVER",
+        llm_config=llm_config,
+        functions=[_run_tests, _summarize, _read_file, _run_command, _git_status, _git_diff],
+    )
     return agent