ci(windows): build inside the MSVC developer shell

msvc-dev-cmd sets the env but rustc still resolved link.exe to Git's GNU
coreutils link (C:\Program Files\Git\usr\bin\link.exe), so build-script
linking failed with 'extra operand'. Run the tauri build in a cmd shell that
sources vcvars64.bat so PATH/LIB/INCLUDE point at the real MSVC toolchain in
the same process.

.gitea/workflows/release.yml

@@ -235,8 +235,10 @@ jobs:
           arch: x64
 
       - name: Build installers
-        shell: bash
+        shell: cmd
-        run: bun run --filter gridline-desktop tauri build
+        run: |
+          call "C:\Program Files (x86)\Microsoft Visual Studio\2022\BuildTools\VC\Auxiliary\Build\vcvars64.bat"
+          bun run --filter gridline-desktop tauri build
 
       - name: Create release and upload Windows assets
         shell: bash