build: integrate Docker functionality

Add environment variables throughout the code base to support Docker
compose integration.

ref: N25B-280

src/control_backend/core/config.py

@@ -1,3 +1,5 @@
+import os
+
 from pydantic import BaseModel
 from pydantic_settings import BaseSettings, SettingsConfigDict
 
@@ -6,9 +8,11 @@ class ZMQSettings(BaseModel):
     internal_pub_address: str = "tcp://localhost:5560"
     internal_sub_address: str = "tcp://localhost:5561"
 
+    external_host: str = "0.0.0.0"
+
 
 class AgentSettings(BaseModel):
-    host: str = "localhost"
+    host: str = os.environ.get("XMPP_HOST", "localhost")
     bdi_core_agent_name: str = "bdi_core"
     belief_collector_agent_name: str = "belief_collector"
     text_belief_extractor_agent_name: str = "text_belief_extractor"
@@ -23,8 +27,8 @@ class AgentSettings(BaseModel):
 
 
 class LLMSettings(BaseModel):
-    local_llm_url: str = "http://localhost:1234/v1/chat/completions"
-    local_llm_model: str = "openai/gpt-oss-20b"
+    local_llm_url: str = os.environ.get("LLM_URL", "http://localhost:1234/v1/") + "chat/completions"
+    local_llm_model: str = os.environ.get("LLM_MODEL", "openai/gpt-oss-20b")
 
 
 class Settings(BaseSettings):