Re-vendor the shared files from sneak/prompts at dd4027b (closes #113)

The shared files are the sneak/prompts copies at dd4027b, with this
repository's own entries after them. make lint and make test each build
one Dockerfile phase without the cache, both covering the frontend
through a node stage; the builder stage waits on both and takes its
version from git describe unless VERSION is given. golangci-lint moves
to v2.14.0 with the new .golangci.yml; one test spells X-Request-ID as
canonicalheader asks. prettier formats only JavaScript, CSS, HTML and
Markdown, so .golangci.yml stays as fetched. script/fmt and
script/fmt-check put ~/.local/bin on PATH, which the shared workflow no
longer does. script/bootstrap keeps a Go only if it is exactly
GO_VERSION, and re-checks the go on PATH after installing.

Model: opus-5-5

script/frontend-test

@@ -1,7 +1,8 @@
 #!/bin/sh
-# script/frontend-test: run the frontend test suite: the unit tests in
-# test/unit/, through the test script in package.json, then the
-# production build, which fails on broken code. The tests print a dot
+# script/frontend-test: run the frontend test suite on the host: the
+# unit tests in test/unit/, through the test script in package.json,
+# then the production build, which fails on broken code. make test runs
+# the same in the frontend stage of Dockerfile. The tests print a dot
 # each; if any fails, they run again with every test listed, and the
 # script fails even if that run passes. NODE_OPTIONS chooses the
 # reporter because yarn adds its arguments after the test files, where
@@ -12,9 +13,9 @@ ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
-    NODE_OPTIONS=--test-reporter=dot timeout 30 yarn --silent run test || {
+    NODE_OPTIONS=--test-reporter=dot timeout 90 yarn --silent run test || {
         echo "--- Rerunning with every test listed for details ---"
-        NODE_OPTIONS=--test-reporter=spec timeout 30 yarn --silent run test
+        NODE_OPTIONS=--test-reporter=spec timeout 90 yarn --silent run test
         exit 1
     }
     timeout 30 yarn build