Move onlyBuiltDependencies into .npmrc so CI's pnpm 10 honors it

pnpm-workspace.yaml's onlyBuiltDependencies (pnpm 10+) wasn't being read
in CI even though that's where pnpm 10 docs say it should live — the
install still bailed with ERR_PNPM_IGNORED_BUILDS. .npmrc is the long-
established, version-agnostic location pnpm honors regardless of the
installed major. Add the allowlist there.

The duplicate entries in pnpm-workspace.yaml and package.json#pnpm stay
in place — they're harmless and serve as documentation for anyone running
older pnpm.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.npmrc

@@ -0,0 +1,11 @@
+; pnpm settings — kept here (rather than in pnpm-workspace.yaml or
+; package.json#pnpm) because .npmrc is honored by every pnpm version we
+; run across CI (pnpm 10 via pnpm/action-setup) and Docker builds (pnpm 9
+; via corepack). The pnpm 10 migration moved onlyBuiltDependencies out of
+; package.json, but .npmrc remains supported and avoids the mismatch.
+only-built-dependencies[]=@nestjs/core
+only-built-dependencies[]=@prisma/client
+only-built-dependencies[]=@prisma/engines
+only-built-dependencies[]=msw
+only-built-dependencies[]=prisma
+only-built-dependencies[]=unrs-resolver