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/release.yml

@@ -22,10 +22,10 @@ jobs:
         # `backend` in config.toml. All three are ort load-dynamic (dlopen)
         # EPs, so this doesn't require the NPU/ROCm/CUDA toolkits to be
         # present on the build host — see breadmill/Cargo.toml.
-        run: cd src && cargo build --release --locked --workspace --features full
+        run: cd src && bash ci/build.sh cargo build --release --locked --workspace --features full
 
       - name: test
-        run: cd src && cargo test --release --locked --workspace --features full
+        run: cd src && bash ci/build.sh cargo test --release --locked --workspace --features full
 
       - name: prepare artifacts
         run: |