socket-scan: address review comments

- Make the Node 24 env-var comment date-agnostic (2026-06-16 has passed)
- Remove the unused Corepack step; this repo has no package.json, so it
  only ever shimmed yarn/pnpm that are never invoked
- Replace dtolnay/rust-toolchain with `rustup update`, matching the
  convention in this repo's other Rust workflows and dropping a
  third-party action from a security workflow

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: kanwalpreetd

.github/workflows/socket-scan.yml

@@ -35,23 +35,18 @@ permissions:
 
 env:
   # Force JS-based GitHub actions (actions/checkout, actions/setup-*, etc.) to
-  # use Node 24 instead of the soon-to-be-deprecated Node 20. Safe to remove
-  # after 2026-06-16 (when Node 24 becomes the default and this becomes a no-op).
+  # use Node 24 instead of Node 20. Remove this once the runner default is Node 24.
   FORCE_JAVASCRIPT_ACTIONS_TO_NODE24: true
 
 jobs:
   socket-scan:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
-      - uses: dtolnay/rust-toolchain@e97e2d8cc328f1b50210efc529dca0028893a2d9 # v1
-        with:
-          toolchain: "1.86.0"
+      - run: rustup update
       - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
         with:
           node-version: "24.18.0"
-      - name: Enable Corepack (yarn/pnpm per repo packageManager)
-        run: corepack enable
 
       - name: Install Socket CLI
         run: npm install -g socket