ci: add dev/beta build track workflows

Mirrors the new stable/beta/dev track feature landing in bread-ecosystem's
bakery. dev-release.yml publishes on every push to dev; beta-release.yml
publishes on a beta-v* tag. Both skip the GitHub Release upload step and
publish to dl.breadway.dev/{dev,beta}/bread/ via gen-index.sh's new TRACK
env var. See bread-ecosystem/docs/release-channels.md for the full policy.

.forgejo/workflows/beta-release.yml

@@ -0,0 +1,49 @@
+name: beta release
+
+# Publishes a beta-track build when a `beta-v*` tag is pushed — a deliberate
+# promotion step, distinct from dev-release.yml's build-on-every-push.
+on:
+  push:
+    tags: ['beta-v*']
+
+jobs:
+  build:
+    runs-on: [self-hosted, hestia]
+    steps:
+      - name: checkout
+        run: |
+          set -euo pipefail
+          rm -rf src && mkdir src
+          git clone --branch "${GITHUB_REF_NAME}" --depth 1 \
+            "https://git.breadway.dev/${GITHUB_REPOSITORY}.git" src
+
+      - name: build
+        run: cd src && cargo build --release --locked
+
+      - name: test
+        run: cd src && cargo test --release --locked --workspace
+
+      - name: prepare artifacts
+        run: |
+          set -euo pipefail
+          VERSION="${GITHUB_REF_NAME#beta-v}"
+          PKG_DIR="/srv/breadway-dl/beta/bread/${VERSION}"
+          mkdir -p "${PKG_DIR}"
+          for bin in breadd bread; do
+            cp "src/target/release/${bin}" "${PKG_DIR}/${bin}-x86_64"
+            strip "${PKG_DIR}/${bin}-x86_64"
+            sha256sum "${PKG_DIR}/${bin}-x86_64" | awk '{print $1}' \
+              > "${PKG_DIR}/${bin}-x86_64.sha256"
+          done
+          cp src/packaging/systemd/breadd.service "${PKG_DIR}/"
+          cp src/bakery.toml "${PKG_DIR}/bakery.toml"
+          ln -sfn "${VERSION}" "/srv/breadway-dl/beta/bread/latest"
+
+      # No GitHub Release upload — beta, like dev, is only distributed via
+      # dl.breadway.dev/beta/.
+      - name: regenerate beta index.json
+        run: |
+          set -euo pipefail
+          rm -rf /tmp/bread-ecosystem-ci
+          git clone https://git.breadway.dev/Breadway/bread-ecosystem.git /tmp/bread-ecosystem-ci
+          TRACK=beta bash /tmp/bread-ecosystem-ci/scripts/gen-index.sh