refactor(ci): extract setup-tauri action and generalize Windows builds (#3702)

This prevents duplication for different Tauri jobs like building the
release packages vs testing a debug build with mock keyring.

```[tasklist]
- [ ] Fix branch protection rules for changed tests
```

---------

Signed-off-by: Reactor Scram <ReactorScram@users.noreply.github.com>

.github/workflows/_rust.yml

@@ -33,6 +33,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: ./.github/actions/setup-rust
+      - uses: ./.github/actions/setup-tauri
       - run: cargo fmt -- --check
       - run: |
           cargo doc --all-features --no-deps --document-private-items ${{ matrix.packages }}
@@ -66,13 +67,24 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: ./.github/actions/setup-rust
+      - uses: ./.github/actions/setup-tauri
       - run: cargo test --all-features ${{ matrix.packages }}
 
   # Runs the Windows client smoke test, built in debug mode. We can't run it in release
   # mode because of a known issue: <https://github.com/firezone/firezone/blob/456e044f882c2bb314e19cc44c0d19c5ad817b7c/rust/windows-client/src-tauri/src/client.rs#L162-L164>
-  windows-smoke-test:
-    name: windows-smoke-test
-    runs-on: windows-2019
+  gui-smoke-test:
+    name: gui-smoke-test-${{ matrix.runs-on }}
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          # Awaiting another PR to generalize the smoke test for Ubuntu
+          #- runs-on: ubuntu-20.04
+          # Broken on 22.04 <https://github.com/firezone/firezone/issues/3699>
+          #- runs-on: ubuntu-22.04
+          - runs-on: windows-2019
+          - runs-on: windows-2022
+    runs-on: ${{ matrix.runs-on }}
     defaults:
       run:
         working-directory: ./rust/windows-client
@@ -85,19 +97,7 @@ jobs:
         with:
           node-version: '20'
       - uses: ./.github/actions/setup-rust
-        with:
-          targets: x86_64-pc-windows-msvc
-        # This is the "Evergreen" bootstrapper from Microsoft
-        # <https://developer.microsoft.com/en-us/microsoft-edge/webview2/?form=MA13LH#download>
-        # Unfortunately, this makes the test non-deterministic.
-        # Controlling the version would be difficult.
-      - name: Download WebView2 bootstrapper
-        run: Invoke-WebRequest -Uri https://go.microsoft.com/fwlink/p/?LinkId=2124703 -OutFile WebView2Installer.exe
-        # This downloads about 200 MB and takes about 5 minutes on my VM
-        # So we could fault in WebView2 from the client exe without the MSI if we needed.
-        # Currently the MSI does this and it's a little janky.
-      - name: Install WebView2
-        run: Start-Process WebView2Installer.exe -ArgumentList "/install" -Wait
+      - uses: ./.github/actions/setup-tauri
       - name: pnpm install
         run: |
           pnpm install
@@ -114,23 +114,24 @@ jobs:
         run: bash scripts/crash-handling-smoke-test.bash
 
   # This should be identical to `build-push-windows-release-artifacts` in `cd.yml` except for the Github permissions, needs tag, and uploading step
-  build-tauri:
-    name: build-tauri-${{ matrix.name }}
-    runs-on: windows-2019
+  build-gui:
+    name: build-gui-${{ matrix.runs-on }}
+    runs-on: ${{ matrix.runs-on }}
     defaults:
       run:
         working-directory: ./rust/windows-client
     strategy:
       fail-fast: false
-      # The matrix is 1x1 to match the style of build-push-linux-release-artifacts
-      # In the future we could try to cross-compile aarch64-windows here.
       matrix:
+        runs-on:
+          # TODO
+          # - ubuntu-20.04
+          - windows-2019
         include:
-          - package: firezone-windows-client
-            artifact: firezone-windows-client
-            name: windows-client
+          # - runs-on: ubuntu-20.04
+          - runs-on: windows-2019
     env:
-      BINARY_DEST_PATH: ${{ matrix.artifact }}
+      BINARY_DEST_PATH: firezone-windows-client
       CONNLIB_LOG_UPLOAD_INTERVAL_SECS: 300
     steps:
       - uses: actions/checkout@v4
@@ -138,8 +139,7 @@ jobs:
         with:
           node-version: '20'
       - uses: ./.github/actions/setup-rust
-        with:
-          targets: x86_64-pc-windows-msvc
+      - uses: ./.github/actions/setup-tauri
       - name: Install pnpm deps
         run: pnpm install
       - name: Build release exe and MSI
@@ -159,24 +159,26 @@ jobs:
           # This might catch regressions in #3384, depending how CI runners
           # handle exit codes
           git diff --exit-code
-      - name: Save Windows client
+      - name: Save GUI client
         uses: actions/upload-artifact@v4
         with:
-          name: ${{ matrix.artifact }}-x64
+          name: ${{ env.BINARY_DEST_PATH }}-x64
           path: |
-            ${{ github.workspace }}/rust/windows-client/${{ matrix.artifact }}-x64.exe
-            ${{ github.workspace }}/rust/windows-client/${{ matrix.artifact }}-x64.exe.sha256sum.txt
-      - name: Save Windows installer
+            ${{ github.workspace }}/rust/windows-client/${{ env.BINARY_DEST_PATH }}-x64.exe
+            ${{ github.workspace }}/rust/windows-client/${{ env.BINARY_DEST_PATH }}-x64.exe.sha256sum.txt
+      - name: Save Windows MSI installer
+        if: ${{ runner.os == 'Windows' }}
         uses: actions/upload-artifact@v4
         with:
-          name: ${{ matrix.artifact }}-x64-msi
+          name: ${{ env.BINARY_DEST_PATH }}-x64-msi
           path: |
-            ${{ github.workspace }}/rust/windows-client/${{ matrix.artifact }}-x64.msi
-            ${{ github.workspace }}/rust/windows-client/${{ matrix.artifact }}-x64.msi.sha256sum.txt
+            ${{ github.workspace }}/rust/windows-client/${{ env.BINARY_DEST_PATH }}-x64.msi
+            ${{ github.workspace }}/rust/windows-client/${{ env.BINARY_DEST_PATH }}-x64.msi.sha256sum.txt
       - name: Save Windows debug symbols
+        if: ${{ runner.os == 'Windows' }}
         uses: actions/upload-artifact@v4
         with:
-          name: ${{ matrix.artifact }}-x64-pdb
+          name: ${{ env.BINARY_DEST_PATH }}-x64-pdb
           path: |
-            ${{ github.workspace }}/rust/windows-client/${{ matrix.artifact }}-x64.pdb
-            ${{ github.workspace }}/rust/windows-client/${{ matrix.artifact }}-x64.pdb.sha256sum.txt
+            ${{ github.workspace }}/rust/windows-client/${{ env.BINARY_DEST_PATH }}-x64.pdb
+            ${{ github.workspace }}/rust/windows-client/${{ env.BINARY_DEST_PATH }}-x64.pdb.sha256sum.txt