feat: Refactor outlets with multilingual support and dynamic queries

- Replace static articles array with dynamic source_keyword queries
- Use MongoDB _id as unique identifier for outlets
- Add multilingual translations (9 languages: ko, en, zh_cn, zh_tw, ja, fr, de, es, it)
- Add OutletService for database operations
- Add outlet migration script with Korean source_keyword matching
- Remove JSON file-based outlet loading
- Add /outlets/{outlet_id}/articles endpoint for dynamic article retrieval

This resolves the design issues with:
1. Static articles array requiring constant updates
2. Lack of multilingual support for outlet names/descriptions
3. Broken image URLs
4. Korean entity matching for article queries

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

services/news-api/backend/app/api/endpoints.py

@@ -2,25 +2,14 @@ from fastapi import APIRouter, HTTPException, Query
 from typing import Optional
 from app.services.article_service import ArticleService
 from app.services.comment_service import CommentService
+from app.services.outlet_service import OutletService
 from app.models.article import ArticleList, Article, ArticleSummary
 from app.models.comment import Comment, CommentCreate, CommentList
+from app.models.outlet import Outlet
 from typing import List
-import json
-import os
 
 router = APIRouter()
 
-# Load outlets data
-OUTLETS_FILE = os.path.join(os.path.dirname(__file__), '../../outlets-extracted.json')
-outlets_data = None
-
-def load_outlets():
-    global outlets_data
-    if outlets_data is None:
-        with open(OUTLETS_FILE, 'r', encoding='utf-8') as f:
-            outlets_data = json.load(f)
-    return outlets_data
-
 @router.get("/{language}/articles", response_model=ArticleList)
 async def get_articles(
     language: str,
@@ -84,28 +73,48 @@ async def get_categories(language: str):
 @router.get("/outlets")
 async def get_outlets(category: Optional[str] = Query(None, description="Filter by category: people, topics, companies")):
     """Get outlets list - people, topics, companies"""
-    data = load_outlets()
-
     if category:
-        if category in ['people', 'topics', 'companies']:
-            return {category: data[category]}
-        else:
-            raise HTTPException(status_code=400, detail=f"Invalid category: {category}. Must be one of: people, topics, companies")
+        # Get outlets for specific category
+        outlets = await OutletService.get_all_outlets(category=category)
+        return {category: outlets}
 
-    return data
+    # Get all outlets grouped by category
+    result = {}
+    for cat in ['people', 'topics', 'companies']:
+        outlets = await OutletService.get_all_outlets(category=cat)
+        result[cat] = outlets
+
+    return result
 
 @router.get("/outlets/{outlet_id}")
 async def get_outlet_by_id(outlet_id: str):
-    """Get specific outlet by ID"""
-    data = load_outlets()
+    """Get specific outlet by ID (_id)"""
+    outlet = await OutletService.get_outlet_by_id(outlet_id)
+    return outlet
 
-    # Search in all categories
-    for category in ['people', 'topics', 'companies']:
-        for outlet in data[category]:
-            if outlet['id'] == outlet_id:
-                return outlet
+@router.get("/{language}/outlets/{outlet_id}/articles")
+async def get_outlet_articles(
+    language: str,
+    outlet_id: str,
+    page: int = Query(1, ge=1, description="Page number"),
+    page_size: int = Query(20, ge=1, le=100, description="Items per page")
+):
+    """Get articles for a specific outlet using source_keyword"""
+    if not ArticleService.validate_language(language):
+        raise HTTPException(status_code=400, detail=f"Unsupported language: {language}")
 
-    raise HTTPException(status_code=404, detail=f"Outlet not found: {outlet_id}")
+    # Get outlet to retrieve source_keyword
+    outlet = await OutletService.get_outlet_by_id(outlet_id)
+
+    # Query articles by source_keyword dynamically
+    articles_result = await ArticleService.get_articles_by_source_keyword(
+        language,
+        outlet['source_keyword'],
+        page,
+        page_size
+    )
+
+    return articles_result
 
 # Comment endpoints
 @router.get("/comments", response_model=CommentList)