Document hosted dialogue API settings in env example

.env.example

@@ -12,3 +12,11 @@ MODEL=openbmb/MiniCPM-o-4_5-gguf
 # Use the local fine-tuned GGUF by default once downloaded.
 RG_VISION_MODEL=models/goblinV1-gguf/gguf/rune-goblin-v46-Q4_K_M.gguf
 RG_VISION_MMPROJ=models/goblinV1-gguf/gguf/rune-goblin-v46-mmproj-f16.gguf
+
+# Story dialogue backend (NPC chat). Active path = hosted OpenAI-compatible API.
+RG_USE_DIALOGUE_API=1
+RG_DIALOGUE_API_URL=http://your-host:8004/v1/chat/completions
+RG_DIALOGUE_API_KEY=sk-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+RG_DIALOGUE_API_MODEL=MiniCPM-V-4.6-Thinking
+# RG_DIALOGUE_MAX_TOKENS=1024   # thinking model: must cover CoT + JSON answer
+# RG_DIALOGUE_API_TIMEOUT=30