修正：changelog 產生器保留既有紀錄，避免部署後更新紀錄被清空

根本原因：Docker build 內沒有 .git，generate-changelog 讀不到 git log 時會把 changelog.json 覆蓋成空清單，導致正式站的更新紀錄分頁變成空白。

影響：正式版更新紀錄分頁的資料完整性；package.json 的 npm start 行為與縮排格式。

修法：
- git 取不到資料（或 0 筆）且既有 changelog.json 非空時，直接沿用不覆蓋
- package.json 的 start 改為 npm run dev，縮排統一為 tab

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

package.json

@@ -1,41 +1,41 @@
 {
-  "name": "badminton-scoreboard",
-  "private": true,
-  "version": "0.0.0",
-  "type": "module",
-  "scripts": {
-    "gen:changelog": "node scripts/generate-changelog.mjs",
-    "predev": "node scripts/generate-changelog.mjs",
-    "dev": "concurrently \"npm:dev:server\" \"npm:dev:client\"",
-    "dev:client": "vite",
-    "dev:server": "node server/server.mjs",
-    "prebuild": "node scripts/generate-changelog.mjs",
-    "build": "tsc -b && vite build",
-    "lint": "eslint .",
-    "preview": "vite preview",
-    "start": "node server/server.mjs"
-  },
-  "dependencies": {
-    "concurrently": "^9.2.1",
-    "dotenv": "^17.4.2",
-    "express": "^5.2.1",
-    "mysql2": "^3.22.0",
-    "react": "^19.2.4",
-    "react-dom": "^19.2.4",
-    "react-router-dom": "^7.14.1"
-  },
-  "devDependencies": {
-    "@eslint/js": "^9.39.4",
-    "@types/node": "^24.12.2",
-    "@types/react": "^19.2.14",
-    "@types/react-dom": "^19.2.3",
-    "@vitejs/plugin-react": "^6.0.1",
-    "eslint": "^9.39.4",
-    "eslint-plugin-react-hooks": "^7.0.1",
-    "eslint-plugin-react-refresh": "^0.5.2",
-    "globals": "^17.4.0",
-    "typescript": "~6.0.2",
-    "typescript-eslint": "^8.58.0",
-    "vite": "^8.0.4"
-  }
-}
+	"name": "badminton-scoreboard",
+	"private": true,
+	"version": "0.0.0",
+	"type": "module",
+	"scripts": {
+		"gen:changelog": "node scripts/generate-changelog.mjs",
+		"predev": "node scripts/generate-changelog.mjs",
+		"dev": "concurrently \"npm:dev:server\" \"npm:dev:client\"",
+		"dev:client": "vite",
+		"dev:server": "node server/server.mjs",
+		"prebuild": "node scripts/generate-changelog.mjs",
+		"build": "tsc -b && vite build",
+		"lint": "eslint .",
+		"preview": "vite preview",
+		"start": "npm run dev"
+	},
+	"dependencies": {
+		"concurrently": "^9.2.1",
+		"dotenv": "^17.4.2",
+		"express": "^5.2.1",
+		"mysql2": "^3.22.0",
+		"react": "^19.2.4",
+		"react-dom": "^19.2.4",
+		"react-router-dom": "^7.14.1"
+	},
+	"devDependencies": {
+		"@eslint/js": "^9.39.4",
+		"@types/node": "^24.12.2",
+		"@types/react": "^19.2.14",
+		"@types/react-dom": "^19.2.3",
+		"@vitejs/plugin-react": "^6.0.1",
+		"eslint": "^9.39.4",
+		"eslint-plugin-react-hooks": "^7.0.1",
+		"eslint-plugin-react-refresh": "^0.5.2",
+		"globals": "^17.4.0",
+		"typescript": "~6.0.2",
+		"typescript-eslint": "^8.58.0",
+		"vite": "^8.0.4"
+	}
+}