refactor: Move to agent architecture

sources/agents/ollama_chat.toml

@@ -0,0 +1,15 @@
+schema_version = 1
+
+extends     = "Ollama Base Chat"
+name        = "Ollama Chat"
+description = "Local Ollama coding chat (qwen2.5-coder)."
+
+model = "qwen2.5-coder:7b"
+tags  = ["chat", "ollama", "local"]
+
+system_prompt = """{{ read_file(":/roles/qt-cpp-developer.md") }}"""
+
+[body.options]
+num_predict = 2048
+temperature = 0.7
+keep_alive  = "5m"