fix(docker): cd into packages/db before building

pnpm --filter runs in the workspace root where tsc finds the root
tsconfig.json instead of packages/db/tsconfig.json. Change into the
package directory so tsc picks up the correct local tsconfig.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

packages/db/package.json

@@ -16,7 +16,7 @@
     }
   },
   "scripts": {
-    "build": "tsc --project .",
+    "build": "tsc",
     "generate": "drizzle-kit generate",
     "migrate": "drizzle-kit migrate",
     "seed": "tsx src/seed.ts",