CI: build inside bread-ecosystem's shared Arch container

Ports breadsearch onto the shared, pinned Arch build image already
proven in breadpad, so this repo's release CI stops installing its
toolchain/GTK4 stack directly on the bare self-hosted runner.

- ci/build.sh + ci/bread-ecosystem.rev: thin wrapper cloning
  bread-ecosystem pinned to a commit sha and delegating to its own
  ci/build.sh.
- dev-release.yml/rc-release.yml/release.yml: route the existing
  build/test cargo invocations through ci/build.sh, unchanged
  otherwise.
- check.yml: fast clippy/test signal on feature/**  and fix/** pushes.

No ci/deps.txt: breadmill's npu/rocm/cuda/openvino features (pulled
in by --features full) all use ort's load-dynamic (dlopen) mode, so
none of them link against a real ONNX Runtime EP at build time —
confirmed against breadmill/Cargo.toml and by breadpad already
building ort with its own rocm feature against the same base image
with no extra packages. The GUI's librsvg system dep is a runtime
icon-loader dependency (bakery.toml's system_deps), not something
linked at build/link time, so the base image's gtk4/gtk4-layer-shell
already cover what compiling breadsearch needs.

.forgejo/workflows/check.yml

@@ -0,0 +1,24 @@
+name: check
+
+# Fast-fail lint/test on short-lived work branches, before it ever reaches
+# main and triggers a dev-track release build.
+on:
+  push:
+    branches: ['feature/**', 'fix/**']
+
+jobs:
+  check:
+    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: clippy
+        run: cd src && bash ci/build.sh cargo clippy --workspace --all-targets --locked --features full -- -D warnings
+
+      - name: test
+        run: cd src && bash ci/build.sh cargo test --workspace --locked --features full