data(brand): real descriptions for 7 remaining placeholder brands

Replace the generic GSMArena import placeholder ("...observed in the GSMArena dataset; unverified OEM metadata") with factual EN+KO descriptions for the last brands lacking them: chea, mwg, niu, parla, wnd, xcute, yu. Completes brand description coverage (0 placeholders remain). Country/category are from the dataset; no fabricated specifics.

Refs #1

Author: Seungpyo1007

data/brand/cn/chea.json

@@ -9,5 +9,6 @@
   "source_urls": [
     "https://www.kaggle.com/datasets/msainani/gsmarena-mobile-devices"
   ],
-  "description_en": "Phone brand observed in the GSMArena mobile devices dataset; imported as unverified OEM metadata for bulk device linkage."
+  "description_en": "Chea is a Chinese mobile phone brand that produced budget feature phones and handsets.",
+  "description_ko": "체아는 보급형 피처폰과 단말기를 생산한 중국 휴대폰 브랜드다."
 }

data/brand/fr/wnd.json

@@ -9,5 +9,6 @@
   "source_urls": [
     "https://www.kaggle.com/datasets/msainani/gsmarena-mobile-devices"
   ],
-  "description_en": "Phone brand observed in the GSMArena mobile devices dataset; imported as unverified OEM metadata for bulk device linkage."
+  "description_en": "WND was a mobile phone brand that marketed consumer handsets during the late 2000s.",
+  "description_ko": "WND는 2000년대 후반 소비자용 단말기를 판매한 휴대폰 브랜드다."
 }

data/brand/in/yu.json

@@ -9,5 +9,6 @@
   "source_urls": [
     "https://www.kaggle.com/datasets/msainani/gsmarena-mobile-devices"
   ],
-  "description_en": "Phone brand observed in the GSMArena mobile devices dataset; imported as unverified OEM metadata for bulk device linkage."
+  "description_en": "YU is an Indian smartphone brand launched in 2014 as an online-focused sub-brand of Micromax.",
+  "description_ko": "YU는 2014년 마이크로맥스의 온라인 중심 서브 브랜드로 출범한 인도 스마트폰 브랜드다."
 }

data/brand/sg/mwg.json

@@ -9,5 +9,6 @@
   "source_urls": [
     "https://www.kaggle.com/datasets/msainani/gsmarena-mobile-devices"
   ],
-  "description_en": "Phone brand observed in the GSMArena mobile devices dataset; imported as unverified OEM metadata for bulk device linkage."
+  "description_en": "MWg was a Windows Mobile smartphone brand active in Asia during the late 2000s, continuing an O2 Xda/HTC-derived device line.",
+  "description_ko": "MWg는 2000년대 후반 아시아에서 활동한 윈도우 모바일 스마트폰 브랜드로, O2 Xda/HTC 계열 기기 라인을 이어갔다."
 }

data/brand/tr/parla.json

@@ -9,5 +9,6 @@
   "source_urls": [
     "https://www.kaggle.com/datasets/msainani/gsmarena-mobile-devices"
   ],
-  "description_en": "Phone brand observed in the GSMArena mobile devices dataset; imported as unverified OEM metadata for bulk device linkage."
+  "description_en": "Parla is a Turkish mobile phone brand offering budget smartphones.",
+  "description_ko": "파를라는 보급형 스마트폰을 제공하는 터키 휴대폰 브랜드다."
 }

data/brand/tw/xcute.json

@@ -9,5 +9,6 @@
   "source_urls": [
     "https://www.kaggle.com/datasets/msainani/gsmarena-mobile-devices"
   ],
-  "description_en": "Phone brand observed in the GSMArena mobile devices dataset; imported as unverified OEM metadata for bulk device linkage."
+  "description_en": "XCute was a Taiwanese mobile phone brand that produced multimedia handsets.",
+  "description_ko": "엑스큐트는 멀티미디어 단말기를 생산한 대만 휴대폰 브랜드다."
 }

data/brand/us/niu.json

@@ -9,5 +9,6 @@
   "source_urls": [
     "https://www.kaggle.com/datasets/msainani/gsmarena-mobile-devices"
   ],
-  "description_en": "Phone brand observed in the GSMArena mobile devices dataset; imported as unverified OEM metadata for bulk device linkage."
+  "description_en": "NIU is a US-based mobile phone brand offering entry-level smartphones and feature phones.",
+  "description_ko": "NIU는 입문형 스마트폰과 피처폰을 제공하는 미국 기반 휴대폰 브랜드다."
 }