Docker: improve build cache reuse (#40351)

* Docker: improve build cache reuse

* Tests: cover Docker build cache layout

* Docker: fix sandbox cache mount continuations

* Docker: document qr-import manifest scope

* Docker: narrow e2e install inputs

* CI: cache Docker builds in workflows

* CI: route sandbox smoke through setup script

* CI: keep sandbox smoke on script path

scripts/e2e/Dockerfile

@@ -1,3 +1,5 @@
+# syntax=docker/dockerfile:1.7
+
 FROM node:22-bookworm@sha256:cd7bcd2e7a1e6f72052feb023c7f6b722205d3fcab7bbcbd2d1bfdab10b1e935
 
 RUN corepack enable
@@ -6,20 +8,26 @@ WORKDIR /app
 
 ENV NODE_OPTIONS="--disable-warning=ExperimentalWarning"
 
-COPY package.json pnpm-lock.yaml pnpm-workspace.yaml tsconfig.json tsconfig.plugin-sdk.dts.json tsdown.config.ts vitest.config.ts vitest.e2e.config.ts openclaw.mjs ./
+COPY package.json pnpm-lock.yaml pnpm-workspace.yaml ./
+COPY ui/package.json ./ui/package.json
+COPY extensions/memory-core/package.json ./extensions/memory-core/package.json
+COPY patches ./patches
+
+RUN --mount=type=cache,id=openclaw-pnpm-store,target=/root/.local/share/pnpm/store,sharing=locked \
+    pnpm install --frozen-lockfile
+
+COPY tsconfig.json tsconfig.plugin-sdk.dts.json tsdown.config.ts vitest.config.ts vitest.e2e.config.ts openclaw.mjs ./
 COPY src ./src
 COPY test ./test
 COPY scripts ./scripts
 COPY docs ./docs
 COPY skills ./skills
-COPY patches ./patches
 COPY ui ./ui
 COPY extensions/memory-core ./extensions/memory-core
 COPY vendor/a2ui/renderers/lit ./vendor/a2ui/renderers/lit
 COPY apps/shared/OpenClawKit/Sources/OpenClawKit/Resources ./apps/shared/OpenClawKit/Sources/OpenClawKit/Resources
 COPY apps/shared/OpenClawKit/Tools/CanvasA2UI ./apps/shared/OpenClawKit/Tools/CanvasA2UI
 
-RUN pnpm install --frozen-lockfile
 RUN pnpm build
 RUN pnpm ui:build