chore(build): migrate to SwiftPM + xTool, add AltStore/SideStore pipeline

- Replace XcodeGen project.yml with Package.swift (SwiftPM)
- Add xtool.yml for xTool cross-platform build configuration
- Add .gitea/workflows/release.yml — builds IPA on tagged release via
  self-hosted macOS runner, uploads to Gitea releases, auto-updates source
- Add altstore-source.json — dual-compatible with AltStore and SideStore
  (top-level downloadURL, ISO 8601 dates, SilverLABS branding)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitea/workflows/release.yml

@@ -0,0 +1,92 @@
+name: Release IPA
+
+on:
+  push:
+    tags:
+      - "v*"
+
+jobs:
+  build:
+    name: Build & Publish IPA
+    runs-on: [self-hosted, macos]
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install xTool
+        run: |
+          if ! command -v xtool &> /dev/null; then
+            curl -fsSL https://xtool.sh/install.sh | bash
+          fi
+
+      - name: Extract version from tag
+        id: version
+        run: echo "VERSION=${GITHUB_REF_NAME#v}" >> $GITHUB_OUTPUT
+
+      - name: Build IPA
+        env:
+          XTOOL_TEAM_ID: ${{ secrets.APPLE_TEAM_ID }}
+          XTOOL_APPLE_ID: ${{ secrets.APPLE_ID }}
+          XTOOL_APP_PASSWORD: ${{ secrets.APPLE_APP_PASSWORD }}
+        run: |
+          xtool archive \
+            --scheme SilverApple \
+            --output SilverApple.ipa
+
+      - name: Compute SHA-256
+        id: sha
+        run: echo "SHA256=$(shasum -a 256 SilverApple.ipa | awk '{print $1}')" >> $GITHUB_OUTPUT
+
+      - name: Get IPA size (bytes)
+        id: size
+        run: echo "SIZE=$(wc -c < SilverApple.ipa | tr -d ' ')" >> $GITHUB_OUTPUT
+
+      - name: Update altstore-source.json
+        run: |
+          DOWNLOAD_URL="https://git.silverlabs.uk/${{ github.repository }}/releases/download/${{ github.ref_name }}/SilverApple.ipa"
+          DATE=$(date -u +"%Y-%m-%dT%H:%M:%SZ")
+          VERSION="${{ steps.version.outputs.VERSION }}"
+          SHA256="${{ steps.sha.outputs.SHA256 }}"
+          SIZE="${{ steps.size.outputs.SIZE }}"
+
+          # Update top-level downloadURL (required by SideStore) and prepend new version entry
+          jq --arg version "$VERSION" \
+             --arg date "$DATE" \
+             --arg url "$DOWNLOAD_URL" \
+             --arg sha "$SHA256" \
+             --argjson size "$SIZE" \
+             '.apps[0].downloadURL = $url |
+              .apps[0].versions = [{"version": $version, "buildVersion": $version, "date": $date,
+                "localizedDescription": "See release notes.", "downloadURL": $url,
+                "sha256": $sha, "size": $size}] + .apps[0].versions' \
+             altstore-source.json > altstore-source.tmp.json
+          mv altstore-source.tmp.json altstore-source.json
+
+      - name: Commit updated AltStore source
+        run: |
+          git config user.name "Gitea Actions"
+          git config user.email "actions@silverlabs.uk"
+          git add altstore-source.json
+          git commit -m "chore(altstore): update source for ${{ github.ref_name }}" || echo "No changes to commit"
+          git push origin HEAD:main
+
+      - name: Create Gitea release and upload IPA
+        env:
+          GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
+        run: |
+          TAG="${{ github.ref_name }}"
+          REPO="${{ github.repository }}"
+          API="https://git.silverlabs.uk/api/v1"
+
+          # Create release
+          RELEASE_ID=$(curl -s -X POST "$API/repos/$REPO/releases" \
+            -H "Authorization: token $GITEA_TOKEN" \
+            -H "Content-Type: application/json" \
+            -d "{\"tag_name\":\"$TAG\",\"name\":\"SilverApple $TAG\",\"body\":\"AltStore release $TAG\",\"draft\":false,\"prerelease\":false}" \
+            | jq -r '.id')
+
+          # Upload IPA asset
+          curl -s -X POST "$API/repos/$REPO/releases/$RELEASE_ID/assets" \
+            -H "Authorization: token $GITEA_TOKEN" \
+            -F "attachment=@SilverApple.ipa;type=application/octet-stream"