fix(ci): run Swift toolchain setup before CodeQL init

CodeQL manual build-mode wraps every step after init in an x86_64
Rosetta shim, under which `brew install` fails on the Apple Silicon
runner ("Cannot install under Rosetta 2 in ARM default prefix").
Move Xcode selection, XcodeGen install, and project generation before
init so they run natively; keep only xcodebuild inside the traced
region for the extractor.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: funsaized

.github/workflows/codeql.yml

@@ -40,15 +40,11 @@ jobs:
       - name: Check out repository
         uses: actions/checkout@v6
 
-      - name: Initialize CodeQL
-        uses: github/codeql-action/init@v3
-        with:
-          languages: ${{ matrix.language }}
-          build-mode: ${{ matrix.build-mode }}
-
-      # Manual build for Swift: the Xcode project is generated by XcodeGen
-      # (project.yml) and is not committed, so CodeQL autobuild cannot find
-      # it. Mirror the build steps from ci.yml so the extractor can trace it.
+      # Swift toolchain setup runs BEFORE init so it executes natively.
+      # CodeQL's manual build-mode tracer wraps every step after init in an
+      # x86_64/Rosetta shim, under which Homebrew refuses to run on Apple
+      # Silicon. The Xcode project is generated by XcodeGen (project.yml) and
+      # is not committed, so it must be generated here.
       - name: Select latest stable Xcode
         if: matrix.language == 'swift'
         uses: maxim-lobanov/setup-xcode@v1
@@ -63,6 +59,14 @@ jobs:
         if: matrix.language == 'swift'
         run: xcodegen generate
 
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v3
+        with:
+          languages: ${{ matrix.language }}
+          build-mode: ${{ matrix.build-mode }}
+
+      # Only the actual compilation runs inside the CodeQL tracing region so
+      # the Swift extractor can observe the build.
       - name: Build (no code signing)
         if: matrix.language == 'swift'
         run: |