ci: optimize workflow to reduce macOS runner usage by 67%

Streamline CI following Point-Free's approach for pure Swift libraries:

Before:
- 4 macOS jobs (Swift 6.0 + 6.2, debug + release)
- 2 Linux jobs (Swift 6.0 + 6.2)
- 1 README validation job
- 1 Documentation job
Total: 8 jobs (5 macOS, 2 Linux, 1 docs)

After:
- 1 macOS job (Swift 6.2 debug + README validation)
- 2 Linux jobs (Swift 6.2 release + Swift 6.0 compat)
- 1 Documentation job
Total: 4 jobs (2 macOS, 2 Linux)

Benefits:
- 60% reduction in macOS runner usage (5 → 2)
- Faster CI execution (Linux is faster than macOS)
- Same coverage: latest Swift, compatibility check, debug/release builds
- macOS for development workflow, Linux for production validation

Rationale:
- swift-html-types has no platform-specific code
- Debug builds catch most issues, release validates optimizations
- Swift 6.0 compatibility checked on Linux (cheaper)
- README validation bundled with main macOS job

Author: coenttb

.github/workflows/ci.yml

@@ -14,20 +14,16 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  # Note: Swift Testing framework requires Swift 6.0+
-  # Tests use @Test and #expect which are not available in Swift 5.x
-  macos-swift60:
-    name: macOS (Swift 6.0)
+  # Primary development workflow: Latest Swift on macOS with debug build
+  # Includes README validation for fast feedback on development machines
+  macos-latest:
+    name: macOS (Swift 6.2, debug)
     runs-on: macos-26
-    strategy:
-      matrix:
-        xcode: ['26.0']
-        config: ['debug', 'release']
     steps:
       - uses: actions/checkout@v5
 
-      - name: Select Xcode ${{ matrix.xcode }}
-        run: sudo xcode-select -s /Applications/Xcode_${{ matrix.xcode }}.app
+      - name: Select Xcode 26.0
+        run: sudo xcode-select -s /Applications/Xcode_26.0.app
 
       - name: Print Swift version
         run: swift --version
@@ -41,45 +37,19 @@ jobs:
             ${{ runner.os }}-spm-
 
       - name: Build
-        run: swift build -c ${{ matrix.config }}
+        run: swift build -c debug
 
       - name: Run tests
-        run: swift test -c ${{ matrix.config }}
-
-  macos-swift62:
-    name: macOS (Swift 6.2)
-    runs-on: macos-26
-    strategy:
-      matrix:
-        xcode: ['26.0']
-        config: ['debug', 'release']
-    steps:
-      - uses: actions/checkout@v5
+        run: swift test -c debug
 
-      - name: Select Xcode ${{ matrix.xcode }}
-        run: sudo xcode-select -s /Applications/Xcode_${{ matrix.xcode }}.app
-
-      - name: Print Swift version
-        run: swift --version
-
-      - name: Cache Swift packages
-        uses: actions/cache@v4
-        with:
-          path: .build
-          key: ${{ runner.os }}-spm-${{ hashFiles('Package.resolved') }}
-          restore-keys: |
-            ${{ runner.os }}-spm-
-
-      - name: Build
-        run: swift build -c ${{ matrix.config }}
-
-      - name: Run tests
-        run: swift test -c ${{ matrix.config }}
+      - name: Run README verification tests
+        run: swift test --filter ReadmeVerificationTests
 
-  linux-swift60:
-    name: Ubuntu (Swift 6.0)
+  # Production validation: Latest Swift on Linux with release build
+  linux-latest:
+    name: Ubuntu (Swift 6.2, release)
     runs-on: ubuntu-latest
-    container: swift:6.0
+    container: swift:6.2
     steps:
       - uses: actions/checkout@v5
 
@@ -91,47 +61,34 @@ jobs:
           restore-keys: ${{ runner.os }}-spm-
 
       - name: Build
-        run: swift build
+        run: swift build -c release
 
       - name: Run tests
-        run: swift test
+        run: swift test -c release
 
-  linux-swift62:
-    name: Ubuntu (Swift 6.2)
+  # Compatibility check: Minimum supported Swift version (6.0)
+  # Note: Swift Testing framework requires Swift 6.0+
+  linux-compat:
+    name: Ubuntu (Swift 6.0, compatibility)
     runs-on: ubuntu-latest
-    container: swift:6.2
+    container: swift:6.0
     steps:
       - uses: actions/checkout@v5
 
       - name: Cache Swift packages
         uses: actions/cache@v4
         with:
           path: .build
-          key: ${{ runner.os }}-spm-${{ hashFiles('Package.resolved') }}
-          restore-keys: ${{ runner.os }}-spm-
+          key: ${{ runner.os }}-swift60-spm-${{ hashFiles('Package.resolved') }}
+          restore-keys: ${{ runner.os }}-swift60-spm-
 
       - name: Build
-        run: swift build
+        run: swift build -c release
 
       - name: Run tests
-        run: swift test
-
-  readme:
-    name: README Code Examples
-    runs-on: macos-26
-    steps:
-      - uses: actions/checkout@v5
-
-      - name: Select Xcode
-        run: sudo xcode-select -s /Applications/Xcode_26.0.app
-
-      - name: Run README verification tests
-        run: swift test --filter ReadmeVerificationTests
-
-      - name: Validate README examples compile
-        run: |
-          echo "✅ All README code examples are verified to compile and work"
+        run: swift test -c release
 
+  # Documentation generation (keep if you're publishing docs)
   documentation:
     name: Documentation
     runs-on: macos-26