ci: add Linux Docker build environment

- Ubuntu 22.04 + webkit2gtk-4.1 + librsvg2 + nodejs + rustup + tauri-cli
- docker-compose: 绑定源码到 /workspace, 持久化 cargo/target 缓存
- 与 GH Actions ubuntu-latest job 依赖保持一致

Dockerfile

@@ -0,0 +1,38 @@
+# Build Kimi Switch Linux packages (deb / AppImage / rpm) inside a clean
+# Ubuntu 22.04 container. Used both locally (`docker compose run`) and as a
+# reference for GH Actions' ubuntu-latest job.
+FROM ubuntu:22.04
+
+ENV DEBIAN_FRONTEND=noninteractive
+ENV CARGO_TERM_COLOR=always
+ENV RUSTUP_HOME=/usr/local/rustup
+ENV CARGO_HOME=/usr/local/cargo
+ENV PATH=/usr/local/cargo/bin:$PATH
+
+RUN apt-get update && apt-get install -y \
+    curl \
+    wget \
+    git \
+    build-essential \
+    pkg-config \
+    libssl-dev \
+    libgtk-3-dev \
+    libayatana-appindicator3-dev \
+    librsvg2-dev \
+    libwebkit2gtk-4.1-dev \
+    libsoup-3.0-dev \
+    libjavascriptcoregtk-4.1-dev \
+    patchelf \
+    file \
+    nodejs \
+    npm \
+    python3 \
+    && rm -rf /var/lib/apt/lists/*
+
+RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain stable --profile minimal
+
+RUN cargo install tauri-cli --version "^2.0" --locked
+
+WORKDIR /workspace
+
+CMD ["/bin/bash"]

docker-compose.yml

@@ -0,0 +1,13 @@
+services:
+  build-linux:
+    build: .
+    container_name: kimiswitch-build-linux
+    volumes:
+      - .:/workspace
+      - cargo-cache:/usr/local/cargo/registry
+      - target-cache:/workspace/src-tauri/target
+    working_dir: /workspace
+
+volumes:
+  cargo-cache:
+  target-cache: