ci: pin install action dependencies

Pin the external actions used by the shared install composite action so the cache-hardening PR satisfies the repository Actions policy.

Author: prd-carapulse[bot]

.github/actions/install/action.yml

@@ -5,12 +5,12 @@ runs:
 
   steps:
     - name: Install node
-      uses: actions/setup-node@v4
+      uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
       with:
         node-version: 18
 
     - name: Install Foundry
-      uses: foundry-rs/foundry-toolchain@v1
+      uses: foundry-rs/foundry-toolchain@c7450ba673e133f5ee30098b3b54f444d3a2ca2d # v1
 
     - name: Install dependencies
       run: yarn install --frozen-lockfile