feat: add IP geolocation tracking and include location in prompts

- Add GeoLite2-City.mmdb database for IP lookup
- Create geoip.py module for IP location services
- Extract client IP from requests and log location info
- Pass location context to LLM prompts for enhanced responses

backend/main.py

@@ -1,4 +1,4 @@
-from fastapi import FastAPI
+from fastapi import FastAPI, Request
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import StreamingResponse, JSONResponse
 from pydantic import BaseModel
@@ -9,6 +9,7 @@ import logging
 
 from prompt import build_prompt, prepare_prompt_context
 from llm import call_ollama, call_vlm_ocr
+from geoip import get_ip_location_text
 
 logging.basicConfig(
     level=logging.INFO,
@@ -43,23 +44,32 @@ def _preview(text: str, limit: int = 80) -> str:
         return value
     return value[:limit] + "..."
 
+def get_client_ip(request: Request) -> str:
+    return request.headers.get("X-Client-IP") or request.client.host if request.client else "unknown"
+
 @app.post("/v1/completions")
-async def create_completion(request: CompletionRequest):
+async def create_completion(request: Request, req: CompletionRequest):
     request_id = str(uuid.uuid4())[:8]
+    client_ip = get_client_ip(request)
+    # 查询 IP 归属地
+    location = get_ip_location_text(client_ip)
+    if location:
+        logger.info("[%s] client_location=%s", request_id, location)
     try:
         logger.info(
-            "[%s] /v1/completions prefix_chars=%d suffix_chars=%d lang=%s prefix_tail='%s' suffix_head='%s'",
+            "[%s] /v1/completions client_ip=%s prefix_chars=%d suffix_chars=%d lang=%s prefix_tail='%s' suffix_head='%s'",
             request_id,
-            len(request.prefix or ""),
-            len(request.suffix or ""),
-            request.languageId,
-            _preview((request.prefix or "")[-120:]),
-            _preview((request.suffix or "")[:120]),
+            client_ip,
+            len(req.prefix or ""),
+            len(req.suffix or ""),
+            req.languageId,
+            _preview((req.prefix or "")[-120:]),
+            _preview((req.suffix or "")[:120]),
         )
-        llm_prefix, llm_suffix = prepare_prompt_context(request.prefix or "", request.suffix or "")
+        llm_prefix, llm_suffix = prepare_prompt_context(req.prefix or "", req.suffix or "")
         logger.info("[%s] llm_input_prefix=%r", request_id, llm_prefix)
         logger.info("[%s] llm_input_suffix=%r", request_id, llm_suffix)
-        prompt = build_prompt(request.prefix, request.suffix, request.languageId)
+        prompt = build_prompt(req.prefix, req.suffix, req.languageId, location=location)
         result = await call_ollama(prompt, tag=f"{request_id}-primary", temperature=0.7)
 
         content = result["content"] or ""