fix(onnx): clean stale cache after GitHub Actions restoration

Move cache cleanup from clone step to build step to handle GitHub Actions
cache timing. Cache restoration occurs after clone but before build, so
stale unpatched files must be deleted in the build step to force CMake
to recopy patched versions from source.

Author: jdalton

packages/onnxruntime/scripts/build.mjs

@@ -167,26 +167,6 @@ async function cloneOnnxSource() {
     printSuccess('wasm_post_build.js (source) patched')
   }
 
-  // Delete stale cached copies in build directory.
-  // This ensures CMake will recopy the patched version from source during configure.
-  // Without this, GitHub Actions cached builds would use old unpatched version.
-  printStep('Removing stale wasm_post_build.js from build cache...')
-  const platform = process.platform === 'darwin' ? 'Darwin' : 'Linux'
-  const postBuildBuildPath = path.join(ONNX_SOURCE_DIR, 'build', platform, 'Release', 'wasm_post_build.js')
-  if (existsSync(postBuildBuildPath)) {
-    await safeDelete(postBuildBuildPath)
-    printSuccess('Stale wasm_post_build.js removed (CMake will recopy from patched source)')
-  }
-
-  // Clear CMake cache to force full reconfiguration.
-  // This ensures CMake recopies all files from source, picking up our patch.
-  printStep('Clearing CMake cache to force reconfiguration...')
-  const cmakeCachePath = path.join(ONNX_SOURCE_DIR, 'build', platform, 'Release', 'CMakeCache.txt')
-  if (existsSync(cmakeCachePath)) {
-    await safeDelete(cmakeCachePath)
-    printSuccess('CMake cache cleared')
-  }
-
   await createCheckpoint('onnxruntime', 'cloned')
 }
 
@@ -202,6 +182,27 @@ async function build() {
 
   const startTime = Date.now()
 
+  // Clean stale cached files before build.
+  // GitHub Actions may have restored old unpatched files from cache after clone step.
+  // Delete them now to force CMake to recopy patched versions from source.
+  printStep('Checking for stale cached build files...')
+  const platform = process.platform === 'darwin' ? 'Darwin' : 'Linux'
+  const buildCacheDir = path.join(ONNX_SOURCE_DIR, 'build', platform, 'Release')
+
+  // Delete cached wasm_post_build.js (CMake will recopy from patched source).
+  const postBuildBuildPath = path.join(buildCacheDir, 'wasm_post_build.js')
+  if (existsSync(postBuildBuildPath)) {
+    await safeDelete(postBuildBuildPath)
+    printSuccess('Removed stale wasm_post_build.js from cache')
+  }
+
+  // Clear CMake cache to force full reconfiguration.
+  const cmakeCachePath = path.join(buildCacheDir, 'CMakeCache.txt')
+  if (existsSync(cmakeCachePath)) {
+    await safeDelete(cmakeCachePath)
+    printSuccess('Cleared CMake cache')
+  }
+
   // ONNX Runtime has its own build script: ./build.sh --config Release --build_wasm
   // We need to pass WASM_ASYNC_COMPILATION=0 via EMCC_CFLAGS environment variable.