Fix CI: Use stable Rust version to avoid compiler crash

- Replace pre-installed Rust 1.89.0 (which has SIGSEGV bug) with rustup
- Install and use Rust 1.75.0 (known stable version)
- This should resolve the tracing-core compilation crash
- Keep all other CI optimizations intact

.forgejo/workflows/ci.yml

@@ -71,9 +71,18 @@ jobs:
           cp -r /tmp/apt-ostree/* .
           cp -r /tmp/apt-ostree/.* . 2>/dev/null || true
 
-      - name: Verify Rust installation
+      - name: Install Rust toolchain
         run: |
-          echo "Using pre-installed Rust from rust:slim-trixie:"
+          # Install rustup to get a stable Rust version
+          curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y
+          . ~/.cargo/env
+          
+          # Use a more stable Rust version (1.75.0 is known to be very stable)
+          rustup install 1.75.0
+          rustup default 1.75.0
+          
+          # Verify Rust version
+          echo "Using Rust version:"
           rustc --version
           cargo --version