fix(planting-service): 排除 prisma 目录修复编译输出路径

prisma/seed.ts 导致 TypeScript 编译时目录结构变化，
dist/main.js 变成 dist/src/main.js

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/services/planting-service/tsconfig.build.json

@@ -1,4 +1,4 @@
 {
   "extends": "./tsconfig.json",
-  "exclude": ["node_modules", "test", "dist", "**/*spec.ts"]
+  "exclude": ["node_modules", "test", "dist", "prisma", "**/*spec.ts"]
 }