Replace manual caching with Swatinem/rust-cache

Switch to the industry-standard Swatinem/rust-cache action which:
- Automatically handles all Rust caching complexity
- Works perfectly with cross-compilation matrix builds
- Doesn't conflict with incremental compilation
- Provides better cache hit rates
- Is more reliable than sccache GHA service

Also added --locked flag to cargo build commands for reproducible builds.

This should significantly improve build times and reliability.

.github/workflows/release.yml

@@ -104,37 +104,16 @@ jobs:
       with:
         targets: ${{ matrix.target }}
     
-    # Cache cargo registry and build artifacts
-    - name: Cache cargo registry
-      uses: actions/cache@v4
+    # Smart caching for Rust builds - handles everything automatically
+    - name: Setup Rust Cache
+      uses: Swatinem/rust-cache@v2
       with:
-        path: |
-          ~/.cargo/bin/
-          ~/.cargo/registry/index/
-          ~/.cargo/registry/cache/
-          ~/.cargo/git/db/
-        key: ${{ runner.os }}-cargo-registry-${{ hashFiles('**/Cargo.lock') }}
-        restore-keys: |
-          ${{ runner.os }}-cargo-registry-
-    
-    # Cache target directory with matrix-specific key
-    - name: Cache target directory
-      uses: actions/cache@v4
-      with:
-        path: codex-rs/target
-        key: ${{ runner.os }}-target-${{ matrix.target }}-${{ hashFiles('**/Cargo.lock') }}-${{ hashFiles('**/*.rs') }}
-        restore-keys: |
-          ${{ runner.os }}-target-${{ matrix.target }}-${{ hashFiles('**/Cargo.lock') }}-
-          ${{ runner.os }}-target-${{ matrix.target }}-
-    
-    # Use sccache for additional compilation caching
-    - name: Install sccache
-      uses: mozilla-actions/[email protected]
-    
-    - name: Configure sccache
-      run: |
-        echo "RUSTC_WRAPPER=sccache" >> $GITHUB_ENV
-        echo "SCCACHE_GHA_ENABLED=true" >> $GITHUB_ENV
+        # Ensure cache is unique per target
+        key: ${{ matrix.target }}
+        # Cache on failure to speed up debugging
+        cache-on-failure: true
+        # Working directory for the cache
+        workspaces: "codex-rs -> target"
         
     - name: Install musl tools (Linux)
       if: contains(matrix.target, 'musl')
@@ -175,9 +154,9 @@ jobs:
         cd codex-rs
         # Use all available cores
         export CARGO_BUILD_JOBS=$(($(nproc || sysctl -n hw.ncpu || echo 2) * 2))
-        # Note: CARGO_INCREMENTAL is disabled when using sccache
         echo "Building with $CARGO_BUILD_JOBS parallel jobs"
-        cargo build --release --target ${{ matrix.target }} --bin coder --bin coder-tui --bin coder-exec
+        # Use --locked to ensure reproducible builds
+        cargo build --release --locked --target ${{ matrix.target }} --bin coder --bin coder-tui --bin coder-exec
         
     - name: Prepare artifacts
       run: |

.github/workflows/rust-release.yml

@@ -95,28 +95,16 @@ jobs:
         with:
           targets: ${{ matrix.target }}
 
-      - uses: actions/cache@v4
+      # Smart caching for Rust builds - handles everything automatically
+      - name: Setup Rust Cache
+        uses: Swatinem/rust-cache@v2
         with:
-          path: |
-            ~/.cargo/bin/
-            ~/.cargo/registry/index/
-            ~/.cargo/registry/cache/
-            ~/.cargo/git/db/
-            ${{ github.workspace }}/codex-rs/target/
-          key: cargo-release-${{ matrix.runner }}-${{ matrix.target }}-release-${{ hashFiles('**/Cargo.lock') }}-${{ hashFiles('**/*.rs') }}
-          restore-keys: |
-            cargo-release-${{ matrix.runner }}-${{ matrix.target }}-release-${{ hashFiles('**/Cargo.lock') }}-
-            cargo-release-${{ matrix.runner }}-${{ matrix.target }}-release-
-      
-      # Use sccache for additional compilation caching
-      - name: Install sccache
-        uses: mozilla-actions/[email protected]
-      
-      - name: Configure sccache
-        shell: bash
-        run: |
-          echo "RUSTC_WRAPPER=sccache" >> $GITHUB_ENV
-          echo "SCCACHE_GHA_ENABLED=true" >> $GITHUB_ENV
+          # Ensure cache is unique per target
+          key: ${{ matrix.target }}
+          # Cache on failure to speed up debugging
+          cache-on-failure: true
+          # Working directory for the cache
+          workspaces: "codex-rs -> target"
 
       - if: ${{ matrix.target == 'x86_64-unknown-linux-musl' || matrix.target == 'aarch64-unknown-linux-musl'}}
         name: Install musl build tools
@@ -128,9 +116,9 @@ jobs:
         run: |
           # Use all available cores
           export CARGO_BUILD_JOBS=$(($(nproc || sysctl -n hw.ncpu || echo 2) * 2))
-          # Note: CARGO_INCREMENTAL is disabled when using sccache
           echo "Building with $CARGO_BUILD_JOBS parallel jobs"
-          cargo build --target ${{ matrix.target }} --release --bin coder
+          # Use --locked to ensure reproducible builds
+          cargo build --target ${{ matrix.target }} --release --locked --bin coder
 
       - name: Stage artifacts
         shell: bash