perf: install lcov via prebuilt binary (#1123)

**Motivation:**  

After several rounds of optimization, the entire CI suite is now limited by the `coverage` job, which in turn is constrained by the `install lcov` step. This step currently takes 3.5 minutes to install `lcov` via `apt`.  

This PR modifies the installation method, switching from `apt` to a prebuilt binary. As a result, the installation time is reduced from 3.5 minutes to just 1 second.  

**Modifications:**  

This PR updates the `lcov` installation process to use a prebuilt binary instead of `apt`.  

**Result:**  

Reduces the installation time from 3.5 minutes to 1 second.

Author: bowenli86

.github/workflows/foundry.yml

@@ -181,10 +181,11 @@ jobs:
           version: stable
 
       # Install LCOV for coverage report generation.
-      - name: Install LCOV
+      - name: Install LCOV (Prebuilt)
         run: |
-          sudo apt-get install -y lcov
-        id: lcov
+          curl -L https://github.com/linux-test-project/lcov/releases/download/v1.16/lcov-1.16.tar.gz | tar xz
+          sudo cp lcov-1.16/bin/* /usr/local/bin/
+          sudo cp -r lcov-1.16/man/* /usr/share/man/
 
       # Build the project and display contract sizes.
       - name: "Forge Build"