fix: init git submodules in CI with HTTPS fallback

The featherchat submodule uses SSH URL which doesn't work in CI.
Convert to HTTPS via git insteadOf before submodule init.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitea/workflows/build.yml

@@ -20,6 +20,11 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Init submodules
+        run: |
+          git config --global url."https://git.manko.yoga/".insteadOf "ssh://git@git.manko.yoga:222/"
+          git submodule update --init --recursive
+
       - name: Install Rust + dependencies
         run: |
           curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y