chore: re-vendor canonical files from prompts at dd4027b (closes #472)

Copies .dockerignore, .gitignore, .prettierignore, check.yml and
REPO_POLICIES.md from sneak/prompts at dd4027b. The repo's own entries
(dist/, release/, yarn files) are kept after the canonical content.

The Dockerfile gets separate lint and test phases. Its last stage
depends on both, checks the git describe version and runs make build.
script/lint, test, check, cibuild and docker are the canonical models.
check-censored moves into the lint phase and test-verify-build into the
test phase. fmt and fmt-check fall back to the nvm-installed node. The
e2e image builds are uncached. Comments that cited the old test caps
now say 60 seconds, and comments that named what runs a script now name
the Dockerfile phase or stage.

Model: opus-5-5

script/test

@@ -1,52 +1,19 @@
 #!/bin/sh
-# script/test: run the test suite.
-#
-# jest runs three worker processes (package.json), not one per CPU core: on a
-# many-core shared host one per core took gigabytes of RAM per run.
-#
-# The timeout bounds a hung suite; it is not a performance budget. On the busy
-# shared build host the suite takes 8-13s with three workers, inside
-# REPO_POLICIES' 20s budget. Inside the image the same suite also pays a cold
-# jest cache and shares the runner with the rest of the build, which is not what
-# that budget describes, so the Dockerfile raises the bound through
-# AUTISTMASK_TEST_TIMEOUT. A cap a healthy suite can trip on a cold cache
-# produces a red that means nothing, and teaches "just run it again".
+# script/test: run the test suite. Testing is a phase of the Dockerfile
+# and this builds that phase alone, on the same terms as script/lint:
+# --target because a phase that is not the last stage is built only when
+# named, --no-cache because a cached test layer is a test that did not
+# run, and a tag so each build replaces the previous image.
 set -eu
 
-ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
-TIMEOUT="${AUTISTMASK_TEST_TIMEOUT:-30}"
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
-    echo "Running tests (timeout ${TIMEOUT}s)..."
-
-    status=0
-    timeout "$TIMEOUT" yarn run test 2>&1 || status=$?
-    [ "$status" -eq 0 ] && return 0
-
-    # 124 is timeout(1) killing the suite. Say so: a kill is not a failed
-    # assertion, and the verbose rerun would only spend the same wall clock
-    # to be killed again.
-    if [ "$status" -eq 124 ]; then
-        echo "tests: TIMED OUT after ${TIMEOUT}s (no assertion failed)" >&2
-        echo "tests: raise AUTISTMASK_TEST_TIMEOUT if the suite is healthy" >&2
-        exit 1
-    fi
-
-    # 125 is timeout(1) itself failing, which here means AUTISTMASK_TEST_TIMEOUT
-    # is not a duration it accepts. The suite never ran, so it neither timed out
-    # nor failed, and the verbose rerun would only reprint the same complaint.
-    if [ "$status" -eq 125 ]; then
-        echo "tests: DID NOT RUN: timeout(1) rejected AUTISTMASK_TEST_TIMEOUT=\"${TIMEOUT}\"" >&2
-        echo "tests: set it to a duration such as 30 or 180 (see timeout(1))" >&2
-        exit 1
-    fi
-
-    echo "--- Rerunning with --verbose for details ---"
-    timeout "$TIMEOUT" yarn run test:verbose 2>&1 || true
-    # Always fail: the first run already proved the tests are broken, so a
-    # flaky pass on the rerun must not turn the build green.
-    exit 1
+    docker build --no-cache \
+        --target test \
+        -t "$("$SCRIPT_DIR/projectname")-test" .
 }
 
 main "$@"