fix(ci): setup MSVC for x86 to fix dependency builds

The x86 (32-bit) build job was failing at "Install dependencies"
(uv sync --frozen --compile) because no cp314-win32 wheels exist for
packages like pyyaml/greenlet; they build from sdist and need the
32-bit MSVC C toolchain on the 64-bit windows-2025 runner.

- The initial attempt used ilammy/msvc-dev-cmd (Node 20). It produced
  deprecation warnings under Node 24 forcing and did not reliably
  activate the env.
- The first inline version (pwsh + vswhere + cmd child) did not make
  the compiler visible to the subsequent uv step.

Replaced with a minimal native approach that is widely proven:
- shell: cmd step (avoids Node and pwsh quoting entirely)
- Direct call ...\\vcvarsall.bat amd64_x86 using the documented path
  for the windows-2025 image (Visual Studio Enterprise 2022).
- set >> %GITHUB_ENV% to propagate PATH/INCLUDE/LIB etc.
- Added where cl + version check so the activation is visible in
  logs for the Setup step.

Uses �md64_x86 (64-bit hosted tools targeting x86) which matches
how the VS components are installed on the runner and is the common
pattern for 32-bit extension builds on 64-bit CI hosts.

Keeps the change strictly to the CI x86 fix. No dep changes.

Author: AAClause

.github/workflows/build_app.yml

@@ -44,6 +44,31 @@ jobs:
         with:
           python-version: 'cpython-3.14-windows-${{ matrix.arch }}-none'
           working-directory: ${{ github.workspace }}/repo
+      - name: Setup MSVC for x86
+        if: matrix.arch == 'x86'
+        shell: cmd
+        run: |
+          @echo off
+          setlocal
+          set "VCVARS="
+          echo Looking for vcvarsall.bat...
+          for /f "delims=" %%f in ('dir /s /b "C:\Program Files*\Microsoft Visual Studio\2022\*\VC\Auxiliary\Build\vcvarsall.bat" 2^>nul') do (
+            set "VCVARS=%%f"
+            goto :found
+          )
+          :found
+          if not defined VCVARS (
+            echo ERROR: vcvarsall.bat not found anywhere under VS 2022
+            dir "C:\Program Files*\Microsoft Visual Studio\2022" 2>&1 | findstr /i "Enterprise Community Professional BuildTools" || echo (no editions visible)
+            exit /b 1
+          )
+          echo Using: %VCVARS%
+          call "%VCVARS%" amd64_x86
+          echo === Verifying 32-bit MSVC toolchain (for uv sdist builds) ===
+          where cl
+          cl 2>&1 | findstr /C:"Version" || echo (no version banner)
+          echo ============================================================
+          set >> %GITHUB_ENV%
       - name: Install dependencies
         working-directory: ${{ github.workspace }}/repo
         run: uv sync --frozen --compile --group build --group test