Yarn 4 Migration (#32253)

Migrates the Overleaf monorepo package manager from npm (v11) to Yarn 4 (v4.9.1) using node-modules linker mode.

GitOrigin-RevId: 50d32ab01955c15e29679eff9e9e9cfb897fab2d

.yarnrc.yml

@@ -0,0 +1,21 @@
+approvedGitRepositories:
+  - "**"
+
+enableGlobalCache: false
+
+enableScripts: true
+
+nodeLinker: node-modules
+
+supportedArchitectures:
+  cpu:
+    - current
+    - arm64
+    - x64
+  libc:
+    - current
+    - glibc
+  os:
+    - current
+    - darwin
+    - linux