ci: migrate all workflows to Blacksmith runners

- CI workflow: Use 4 vCPU for lightweight jobs (version-check, fmt, audit, ci-success)
              Use 32 vCPU for compilation jobs (clippy, test, build-check, gui-check)
- Release workflow: Use 4 vCPU for prepare/release jobs, 32 vCPU for builds
- Use native ARM runners for Linux ARM64 builds (no cross-compilation needed)
- Replace Swatinem/rust-cache with useblacksmith/rust-cache@v3 for Blacksmith runners
- Increase Rust threads to 32 for 32 vCPU runners (was 16)
- Add concurrency groups to prevent CI overload when many PRs merge
- All Blacksmith runners use 4x faster colocated cache automatically

Runner allocation:
- Small CI jobs: blacksmith-4vcpu-ubuntu-2404
- Heavy compilation: blacksmith-32vcpu-ubuntu-2404, blacksmith-32vcpu-windows-2025
- Linux ARM64: blacksmith-32vcpu-ubuntu-2404-arm (native, no cross-compile)
- macOS: macos-latest (Blacksmith doesn't support macOS)

Author: factorydroid

.github/workflows/ci.yml

@@ -9,37 +9,37 @@ on:
 env:
   CARGO_TERM_COLOR: always
   RUST_BACKTRACE: 1
-  # Nightly multithreaded frontend for faster compilation
-  RUSTFLAGS: "-Zthreads=16"
+  # Nightly multithreaded frontend for faster compilation (32 threads for 32 vCPU runners)
+  RUSTFLAGS: "-Zthreads=32"
   # Sparse registry for faster index updates
   CARGO_REGISTRIES_CRATES_IO_PROTOCOL: sparse
   # Incremental compilation off for CI (more reproducible, better caching)
   CARGO_INCREMENTAL: 0
 
-# Ensure only one CI run per branch at a time
+# Ensure only one CI run per branch at a time - prevents overloading when many PRs merge
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
 jobs:
   # ==========================================================================
-  # Version consistency check
+  # Version consistency check (lightweight - 4 vCPU)
   # ==========================================================================
   version-check:
     name: CLI Version Check
-    runs-on: ubuntu-latest
+    runs-on: blacksmith-4vcpu-ubuntu-2404
     steps:
       - uses: actions/checkout@v4
 
       - name: Verify CLI version consistency
         run: ./scripts/check-cli-version.sh
 
   # ==========================================================================
-  # Setup job to prepare shared cache
+  # Setup job to prepare shared cache (lightweight - 4 vCPU)
   # ==========================================================================
   setup-cache:
     name: Setup Cache
-    runs-on: ubuntu-latest
+    runs-on: blacksmith-4vcpu-ubuntu-2404
     outputs:
       cache-key: ${{ steps.cache-key.outputs.key }}
     steps:
@@ -55,7 +55,7 @@ jobs:
   # ==========================================================================
   fmt:
     name: Format
-    runs-on: ubuntu-latest
+    runs-on: blacksmith-4vcpu-ubuntu-2404
     steps:
       - uses: actions/checkout@v4
 
@@ -69,7 +69,7 @@ jobs:
 
   clippy:
     name: Clippy
-    runs-on: ubuntu-latest
+    runs-on: blacksmith-32vcpu-ubuntu-2404
     needs: setup-cache
     steps:
       - uses: actions/checkout@v4
@@ -84,8 +84,8 @@ jobs:
         with:
           components: clippy
 
-      - name: Setup Rust cache
-        uses: Swatinem/rust-cache@v2
+      - name: Setup Rust cache (Blacksmith optimized)
+        uses: useblacksmith/rust-cache@v3
         with:
           prefix-key: "rust-clippy"
           shared-key: ${{ needs.setup-cache.outputs.cache-key }}
@@ -94,7 +94,7 @@ jobs:
         run: cargo +nightly clippy --workspace --all-targets --all-features --exclude cortex-gui -- -D warnings
 
   # ==========================================================================
-  # Test jobs - Matrix for all platforms
+  # Test jobs - Matrix for all platforms (32 vCPU for compilation)
   # ==========================================================================
   test:
     name: Test (${{ matrix.name }})
@@ -105,11 +105,11 @@ jobs:
       matrix:
         include:
           - name: ubuntu
-            runner: ubuntu-latest
+            runner: blacksmith-32vcpu-ubuntu-2404
           - name: macos
             runner: macos-latest
           - name: windows
-            runner: windows-latest
+            runner: blacksmith-32vcpu-windows-2025
     steps:
       - uses: actions/checkout@v4
 
@@ -122,7 +122,15 @@ jobs:
       - name: Install Rust nightly
         uses: dtolnay/rust-toolchain@nightly
 
-      - name: Setup Rust cache
+      - name: Setup Rust cache (Blacksmith optimized)
+        if: contains(matrix.runner, 'blacksmith')
+        uses: useblacksmith/rust-cache@v3
+        with:
+          prefix-key: "rust-test-${{ matrix.name }}"
+          shared-key: ${{ needs.setup-cache.outputs.cache-key }}
+      
+      - name: Setup Rust cache (non-Blacksmith)
+        if: "!contains(matrix.runner, 'blacksmith')"
         uses: Swatinem/rust-cache@v2
         with:
           prefix-key: "rust-test-${{ matrix.name }}"
@@ -131,10 +139,10 @@ jobs:
       - name: Run tests
         run: cargo +nightly test --workspace --all-features --exclude cortex-gui
         env:
-          RUSTFLAGS: "-Zthreads=16"
+          RUSTFLAGS: "-Zthreads=32"
 
   # ==========================================================================
-  # Build check - All platforms
+  # Build check - All platforms (32 vCPU for compilation)
   # ==========================================================================
   build-check:
     name: Build Check (${{ matrix.name }})
@@ -145,11 +153,11 @@ jobs:
       matrix:
         include:
           - name: ubuntu
-            runner: ubuntu-latest
+            runner: blacksmith-32vcpu-ubuntu-2404
           - name: macos
             runner: macos-latest
           - name: windows
-            runner: windows-latest
+            runner: blacksmith-32vcpu-windows-2025
     steps:
       - uses: actions/checkout@v4
 
@@ -162,7 +170,15 @@ jobs:
       - name: Install Rust nightly
         uses: dtolnay/rust-toolchain@nightly
 
-      - name: Setup Rust cache
+      - name: Setup Rust cache (Blacksmith optimized)
+        if: contains(matrix.runner, 'blacksmith')
+        uses: useblacksmith/rust-cache@v3
+        with:
+          prefix-key: "rust-build-${{ matrix.name }}"
+          shared-key: ${{ needs.setup-cache.outputs.cache-key }}
+      
+      - name: Setup Rust cache (non-Blacksmith)
+        if: "!contains(matrix.runner, 'blacksmith')"
         uses: Swatinem/rust-cache@v2
         with:
           prefix-key: "rust-build-${{ matrix.name }}"
@@ -171,10 +187,10 @@ jobs:
       - name: Check build
         run: cargo +nightly check --workspace --all-features --exclude cortex-gui
         env:
-          RUSTFLAGS: "-Zthreads=16"
+          RUSTFLAGS: "-Zthreads=32"
 
   # ==========================================================================
-  # GUI Check - All platforms
+  # GUI Check - All platforms (32 vCPU for compilation)
   # ==========================================================================
   gui-check:
     name: GUI Check (${{ matrix.name }})
@@ -185,11 +201,11 @@ jobs:
       matrix:
         include:
           - name: ubuntu
-            runner: ubuntu-latest
+            runner: blacksmith-32vcpu-ubuntu-2404
           - name: macos
             runner: macos-latest
           - name: windows
-            runner: windows-latest
+            runner: blacksmith-32vcpu-windows-2025
     steps:
       - uses: actions/checkout@v4
 
@@ -205,7 +221,7 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y libgtk-3-dev libwebkit2gtk-4.1-dev libappindicator3-dev librsvg2-dev patchelf libglib2.0-dev
       
-      - name: Cache npm
+      - name: Cache npm (Blacksmith 4x faster cache)
         uses: actions/cache@v4
         with:
           path: |
@@ -226,7 +242,15 @@ jobs:
       - name: Install Rust nightly
         uses: dtolnay/rust-toolchain@nightly
 
-      - name: Setup Rust cache
+      - name: Setup Rust cache (Blacksmith optimized)
+        if: contains(matrix.runner, 'blacksmith')
+        uses: useblacksmith/rust-cache@v3
+        with:
+          prefix-key: "rust-gui-${{ matrix.name }}"
+          shared-key: ${{ needs.setup-cache.outputs.cache-key }}
+      
+      - name: Setup Rust cache (non-Blacksmith)
+        if: "!contains(matrix.runner, 'blacksmith')"
         uses: Swatinem/rust-cache@v2
         with:
           prefix-key: "rust-gui-${{ matrix.name }}"
@@ -235,21 +259,21 @@ jobs:
       - name: Check GUI build
         run: cargo +nightly check -p cortex-gui
         env:
-          RUSTFLAGS: "-Zthreads=16"
+          RUSTFLAGS: "-Zthreads=32"
 
   # ==========================================================================
-  # Security Audit
+  # Security Audit (lightweight - 4 vCPU)
   # ==========================================================================
   audit:
     name: Security Audit
-    runs-on: ubuntu-latest
+    runs-on: blacksmith-4vcpu-ubuntu-2404
     permissions:
       checks: write
       contents: read
     steps:
       - uses: actions/checkout@v4
 
-      - name: Cache cargo-audit
+      - name: Cache cargo-audit (Blacksmith 4x faster cache)
         uses: actions/cache@v4
         with:
           path: |
@@ -262,11 +286,11 @@ jobs:
           token: ${{ secrets.GITHUB_TOKEN }}
 
   # ==========================================================================
-  # Final status check (for branch protection)
+  # Final status check (for branch protection) - lightweight - 4 vCPU
   # ==========================================================================
   ci-success:
     name: CI Success
-    runs-on: ubuntu-latest
+    runs-on: blacksmith-4vcpu-ubuntu-2404
     needs: [version-check, fmt, clippy, test, build-check, gui-check, audit]
     if: always()
     steps:

.github/workflows/homebrew.yml

@@ -10,9 +10,10 @@ on:
         required: true
 
 jobs:
+  # Lightweight job - 4 vCPU Blacksmith runner
   update-homebrew:
     name: Update Homebrew Formula
-    runs-on: ubuntu-latest
+    runs-on: blacksmith-4vcpu-ubuntu-2404
     steps:
       - uses: actions/checkout@v4
 

.github/workflows/publish-r2.yml

@@ -56,11 +56,11 @@ permissions:
 
 jobs:
   # ==========================================================================
-  # Download artifacts from Release workflow and publish to R2
+  # Download artifacts from Release workflow and publish to R2 (lightweight - 4 vCPU)
   # ==========================================================================
   publish:
     name: Publish to R2
-    runs-on: ubuntu-latest
+    runs-on: blacksmith-4vcpu-ubuntu-2404
 
     steps:
       - uses: actions/checkout@v4