fix package.json build (#60)

<!-- CURSOR_SUMMARY -->
> [!NOTE]
> **Low Risk**
> Low risk config-only change that affects dependency build permissions
during install; risk is limited to pnpm install/build behavior if the
allowlist is incomplete or incorrect.
> 
> **Overview**
> Fixes pnpm build configuration by removing the
`pnpm.onlyBuiltDependencies` block from `package.json` and introducing
`pnpm-workspace.yaml` with an `allowBuilds` allowlist.
> 
> This explicitly permits native/build-time dependencies (e.g.,
`@embedded-postgres/linux-x64`, `@swc/core`, `sharp`, `esbuild`) to run
their install/build steps under pnpm.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
a8d42cc. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: callicles

package.json

@@ -46,11 +46,6 @@
     "workflow": "4.1.0-beta.60",
     "zod": "^3.24.1"
   },
-  "pnpm": {
-    "onlyBuiltDependencies": [
-      "@embedded-postgres/linux-x64"
-    ]
-  },
   "devDependencies": {
     "@biomejs/biome": "2.4.4",
     "@playwright/test": "^1.58.2",

pnpm-workspace.yaml

@@ -0,0 +1,8 @@
+allowBuilds:
+  "@embedded-postgres/linux-x64": true
+  "@nestjs/core": true
+  "@swc/core": true
+  cbor-extract: true
+  esbuild: true
+  protobufjs: true
+  sharp: true