feat(launcher): Linux AppImage 1.0.2, Gitea sync + CI, manual pack script

- Add pack:linux (AppImage x64), linux/appImage artifact names in package.json.
- Gitea sync: parallel build-electron-linux, merge Windows+Linux into Gitea upload;
  rename Windows artifact to electron-dist-windows.
- Fractured launcher CI: electron-launcher-windows + electron-launcher-linux jobs.
- scripts/manual-pack-linux.sh for local test builds from current tree.
- Normalize Gitea base_url (prepend https if missing); baked channel uses full URL.

Co-authored-by: Cursor <cursoragent@cursor.com>

.github/workflows/gitea-release-sync.yml

@@ -13,8 +13,8 @@
 # Release on github.com (Releases → Draft/new release → Publish). The workflow
 # definition must exist on the repo DEFAULT branch (GitHub runs it from there).
 #
-# Steps: build Electron using launcher sources from DEFAULT BRANCH (so tags never miss
-# launcher files), checkout tag only for a consistent tree → download release attachments → Gitea.
+# Steps: Windows (NSIS+portable) + Linux (AppImage) in parallel, launcher from DEFAULT BRANCH
+# overlay on tag checkout → merge with GitHub release assets → upload all to Gitea.
 #
 # Secrets: GITEA_BASE_URL, GITEA_TOKEN, GITEA_OWNER, GITEA_REPO
 # Optional variable: GITEA_TARGET_REF (see tools/fractured-launcher-electron/README.md)
@@ -102,11 +102,61 @@ jobs:
 
       - uses: actions/upload-artifact@v4
         with:
-          name: electron-dist
+          name: electron-dist-windows
           path: launcher-publish/
 
+  build-electron-linux:
+    needs: meta
+    if: github.repository == 'Dawnforger/Fractured'
+    runs-on: ubuntu-latest
+    timeout-minutes: 45
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ needs.meta.outputs.tag }}
+
+      - name: Overlay launcher from default branch
+        shell: bash
+        run: |
+          set -euo pipefail
+          DB="${{ github.event.repository.default_branch }}"
+          git fetch --no-tags --depth=1 origin "+refs/heads/${DB}:refs/remotes/origin/${DB}"
+          git checkout "origin/${DB}" -- tools/fractured-launcher-electron
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: npm
+          cache-dependency-path: tools/fractured-launcher-electron/package-lock.json
+
+      - name: Install and pack (AppImage)
+        working-directory: tools/fractured-launcher-electron
+        run: |
+          npm ci
+          npm run pack:linux
+
+      - name: Stage Linux launcher for upload
+        shell: bash
+        run: |
+          set -euo pipefail
+          mkdir -p launcher-linux-publish
+          shopt -s nullglob
+          cp -f tools/fractured-launcher-electron/dist/*.AppImage launcher-linux-publish/ 2>/dev/null || true
+          cp -f tools/fractured-launcher-electron/dist/*.yml launcher-linux-publish/ 2>/dev/null || true
+          cp -f tools/fractured-launcher-electron/dist/*.blockmap launcher-linux-publish/ 2>/dev/null || true
+          ls -la launcher-linux-publish/
+          if ! compgen -G "launcher-linux-publish/*.AppImage" > /dev/null; then
+            echo "No AppImage under dist/ — electron-builder linux target failed" >&2
+            exit 1
+          fi
+
+      - uses: actions/upload-artifact@v4
+        with:
+          name: electron-dist-linux
+          path: launcher-linux-publish/
+
   sync-gitea:
-    needs: [meta, build-electron]
+    needs: [meta, build-electron, build-electron-linux]
     if: github.repository == 'Dawnforger/Fractured'
     runs-on: ubuntu-latest
     env:
@@ -126,8 +176,13 @@ jobs:
 
       - uses: actions/download-artifact@v4
         with:
-          name: electron-dist
-          path: /tmp/electron
+          name: electron-dist-windows
+          path: /tmp/electron-win
+
+      - uses: actions/download-artifact@v4
+        with:
+          name: electron-dist-linux
+          path: /tmp/electron-linux
 
       - name: Merge GitHub release assets + Electron build
         env:
@@ -150,7 +205,7 @@ jobs:
             cat /tmp/dl.err || true
           fi
           shopt -s nullglob
-          for f in /tmp/electron/*; do
+          for f in /tmp/electron-win/* /tmp/electron-linux/*; do
             if [ -f "$f" ]; then
               cp -f "$f" combined/
             fi