Deploy main eacf1e7 to prod

Replaces #559, which conflicted.

Model: opus-5-5

Dockerfile.browser

@@ -0,0 +1,29 @@
+# Browser test image, built by script/test-browser (make test-browser). It
+# runs the test in internal/server that loads the pages in a headless
+# browser under the real Content-Security-Policy. That test is built only
+# with the browser build tag, so make test leaves it out. Here the browser
+# comes from a digest-pinned image, and if it is missing the test fails.
+
+# golang:1.26.1-bookworm, 2026-03-17: the builder stage's image in Dockerfile.
+FROM golang:1.26.1-bookworm@sha256:4465644228bc2857a954b092167e12aa59c006a3492282a6c820bf4755fd64a4 AS build
+
+WORKDIR /src
+
+COPY go.mod go.sum ./
+RUN go mod download
+
+COPY . .
+
+# The test binary embeds the templates and static files, so the browser
+# stage needs nothing else. It is built with cgo off and -p 4 keeps the
+# compile's memory down, both as in the test phase of Dockerfile.
+RUN make assets && CGO_ENABLED=0 go test -c -p 4 -tags browser -o /browser.test ./internal/server
+
+# chromedp/headless-shell:151.0.7922.109 (Debian trixie), 2026-08-11. The
+# browser is on PATH as headless-shell, where the test's browser library
+# looks for it.
+FROM chromedp/headless-shell:151.0.7922.109@sha256:2d349b544a1ea6b5b5fd7c0fe99215ff662339c57407ee2e8c0a11af93516b04 AS browser
+
+COPY --from=build /browser.test /browser.test
+
+RUN /browser.test -test.v -test.timeout 90s -test.run '^TestAlpineRunsUnderTheSecurityPolicy$'