feat(packaging): open files from argv, ship Windows MSI installer (#36)

Cross-platform prerequisite for OS-level file associations: the boot
task now consumes `std::env::args_os().nth(1)` as a path and dispatches
`Message::OpenRecent` for it. Flag-style args (starting with `-`) are
ignored, and `OpenRecent` already does the file-existence check, so a
bogus path lands as a clean command-line error instead of a panic.

Linux: the AppImage's desktop entry adds `image/vnd.dwg` alongside the
existing `image/vnd.dxf` MIME type and grows a `%f` placeholder in
`Exec=` so the launcher forwards the picked file path. Once the
AppImage is integrated with the system (xdg-mime / AppImageLauncher),
double-clicking a .dwg / .dxf opens it in Open CAD Studio.

Windows: new `packaging/windows/main.wxs` defines an MSI installer —
per-machine install to `Program Files\Open CAD Studio`, Start Menu
shortcut, `MajorUpgrade` so newer MSIs replace older ones, and a
single ProgID `OpenCADStudio.Drawing` that owns both `.dwg` and
`.dxf` and launches the exe with the file as `argv[1]`. The icon is
pulled from the SVG logo, converted to multi-resolution ICO at build
time with the runner's pre-installed ImageMagick. CI now also runs
`candle` / `light` (WiX Toolset 3, pre-installed on `windows-latest`)
and uploads both the bare `.exe` (portable) and `.msi` (installer)
to the release.

macOS Info.plist already declares the DWG / DXF UTIs; combined with
the argv-handling change above, double-clicking a drawing in Finder
will open it in Open CAD Studio without further packaging changes.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.github/workflows/release.yml

@@ -78,13 +78,53 @@ jobs:
       - name: Build
         run: cargo build --release
 
-      - name: Upload exe to release
+      - name: Convert SVG icon to ICO
+        shell: pwsh
+        run: |
+          # ImageMagick is pre-installed on windows-latest. The
+          # auto-resize generates every size Explorer / Add-Remove
+          # Programs / the Start Menu shortcut may request from a
+          # single source SVG.
+          magick assets/logo.svg `
+            -define icon:auto-resize=16,24,32,48,64,128,256 `
+            packaging/windows/AppIcon.ico
+
+      - name: Build MSI installer
+        shell: pwsh
+        run: |
+          $version = "${{ github.ref_name }}" -replace '^v', ''
+          if (-not $version) { $version = "0.0.0" }
+          # WiX Toolset 3.x is pre-installed on windows-latest; $env:WIX
+          # points to the install root. candle compiles .wxs → .wixobj
+          # and light links it into the final .msi.
+          $candle = Join-Path $env:WIX "bin\candle.exe"
+          $light  = Join-Path $env:WIX "bin\light.exe"
+          & $candle -arch x64 `
+            -dVersion=$version `
+            -dSource=target\release\OpenCADStudio.exe `
+            -dIcon=packaging\windows\AppIcon.ico `
+            packaging\windows\main.wxs `
+            -out packaging\windows\main.wixobj
+          if ($LASTEXITCODE -ne 0) { throw "candle failed" }
+          & $light packaging\windows\main.wixobj -out OpenCADStudio.msi
+          if ($LASTEXITCODE -ne 0) { throw "light failed" }
+
+      - name: Upload artifacts to release
         if: github.event_name == 'release'
+        shell: pwsh
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
-          mv target/release/OpenCADStudio.exe OpenCADStudio-${{ github.ref_name }}-windows-x86_64.exe
-          gh release upload ${{ github.ref_name }} OpenCADStudio-${{ github.ref_name }}-windows-x86_64.exe --clobber --repo ${{ github.repository }}
+          $tag = "${{ github.ref_name }}"
+          # Ship both the bare .exe (portable, no install) and the
+          # .msi (installer with Start Menu shortcut + .dwg / .dxf
+          # file association). Users pick the form they want.
+          Move-Item target\release\OpenCADStudio.exe "OpenCADStudio-$tag-windows-x86_64.exe"
+          Move-Item OpenCADStudio.msi "OpenCADStudio-$tag-windows-x86_64.msi"
+          gh release upload $tag `
+            "OpenCADStudio-$tag-windows-x86_64.exe" `
+            "OpenCADStudio-$tag-windows-x86_64.msi" `
+            --clobber --repo ${{ github.repository }}
 
   build-macos:
     runs-on: macos-14    # Apple Silicon (arm64) only