ci: add libghostty-vt source tarball to tip release

Add a source-tarball-lib-vt job that builds the stripped lib-vt
dist tarball and publishes it as libghostty-vt-source.tar.gz to
the tip release. Also downsize the source-tarball runner from -md
to -sm since it does not need the extra resources.

.github/workflows/release-tip.yml

@@ -163,7 +163,7 @@ jobs:
           github.ref_name == 'main'
         )
       )
-    runs-on: namespace-profile-ghostty-md
+    runs-on: namespace-profile-ghostty-sm
     env:
       ZIG_LOCAL_CACHE_DIR: /zig/local-cache
       ZIG_GLOBAL_CACHE_DIR: /zig/global-cache
@@ -206,6 +206,60 @@ jobs:
             ghostty-source.tar.gz.minisig
           token: ${{ secrets.GH_RELEASE_TOKEN }}
 
+  source-tarball-lib-vt:
+    needs: [setup]
+    if: |
+      needs.setup.outputs.should_skip != 'true' &&
+      (
+        github.event_name == 'workflow_dispatch' ||
+        (
+          github.repository_owner == 'ghostty-org' &&
+          github.ref_name == 'main'
+        )
+      )
+    runs-on: namespace-profile-ghostty-sm
+    env:
+      ZIG_LOCAL_CACHE_DIR: /zig/local-cache
+      ZIG_GLOBAL_CACHE_DIR: /zig/global-cache
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      - name: Setup Cache
+        uses: namespacelabs/nscloud-cache-action@a90bb5d4b27522ce881c6e98eebd7d7e6d1653f9 # v1.4.2
+        with:
+          path: |
+            /nix
+            /zig
+      - uses: cachix/install-nix-action@51f3067b56fe8ae331890c77d4e454f6d60615ff # v31.10.2
+        with:
+          nix_path: nixpkgs=channel:nixos-unstable
+      - uses: cachix/cachix-action@1eb2ef646ac0255473d23a5907ad7b04ce94065c # v17
+        with:
+          name: ghostty
+          authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
+      - name: Create Tarball
+        run: |
+          rm -rf zig-out/dist
+          nix develop -c zig build dist -Demit-lib-vt=true
+          cp zig-out/dist/*.tar.gz libghostty-vt-source.tar.gz
+
+      - name: Sign Tarball
+        run: |
+          echo -n "${{ secrets.MINISIGN_KEY }}" > minisign.key
+          echo -n "${{ secrets.MINISIGN_PASSWORD }}" > minisign.password
+          nix develop -c minisign -S -m libghostty-vt-source.tar.gz -s minisign.key < minisign.password
+
+      - name: Update Release
+        uses: softprops/action-gh-release@153bb8e04406b158c6c84fc1615b65b24149a1fe # v2.6.1
+        with:
+          name: 'Ghostty Tip ("Nightly")'
+          prerelease: true
+          tag_name: tip
+          target_commitish: ${{ github.sha }}
+          files: |
+            libghostty-vt-source.tar.gz
+            libghostty-vt-source.tar.gz.minisig
+          token: ${{ secrets.GH_RELEASE_TOKEN }}
+
   build-macos:
     needs: [setup]
     if: |