feat(editor): add Markdown rendering for ghost text and optimize prompt system

- Implement Markdown parsing for ghost text using Milkdown parser
- Add support for both block and inline content in ghost text
- Refactor prompt system with comprehensive rules and examples
- Adjust LLM parameters: increase temperature to 0.7, add repeat_penalty
- Add CSS styles for formatted ghost text (bold, italic, code, links)
- Add documentation for Copilot prompt system and ghost text rendering

backend/llm.py

@@ -6,7 +6,6 @@ from typing import AsyncGenerator
 OLLAMA_MODEL = os.getenv('OLLAMA_MODEL', 'gpt-oss:20b')
 OLLAMA_HOST = os.getenv('OLLAMA_HOST', 'http://192.168.0.120:11434')
 
-# 移除 /v1/ 后缀（如果有的话），因为 Ollama Python 包使用原生 API
 if OLLAMA_HOST.endswith('/v1/'):
     OLLAMA_HOST = OLLAMA_HOST[:-4]
 elif OLLAMA_HOST.endswith('/v1'):
@@ -29,9 +28,10 @@ async def stream_openai(prompt: str) -> AsyncGenerator[str, None]:
             messages=[{'role': 'user', 'content': prompt}],
             stream=True,
             options={
-                'num_predict': 8192,
-                'temperature': 0.2,
-            }
+                'temperature': 0.7,
+                'repeat_penalty': 1.1,
+            },
+            think='high'
         )
         print(f"[LLM] Got stream object, starting iteration...")