Targets whose home page redirects are checked at /robots.txt (closes #190)

The browser follows a redirect, so the figures for the AWS Console, Akamai,
B2 and the S3 regions also timed the page it led to, for B2 and S3 on
another host. The Google Cloud Console redirects only requests that do not
say they come from another site; browsers say so and get a 403 directly.
Each of these targets is now checked at /robots.txt on its own host, which
answers without a redirect. README.md says what a figure includes. Chrome
opens a new connection for most S3 checks, so far regions now read higher.

Model: opus-5-5

TODO.md

@@ -23,6 +23,18 @@ Run `make frontend-viewport-test` in CI as its own step; it is not part of
 
 # Completed Steps
 
+- 2026-10-26: a target whose home page answers with a redirect is checked at
+  `/robots.txt` on the same host, which answers without one
+  ([#190](https://git.eeqj.de/sneak/netwatch/issues/190)). These are the AWS
+  Console, Akamai, B2 and the 8 S3 regions, and the Google Cloud Console, whose
+  home page redirects a request that does not say it comes from another site.
+  The browser follows a redirect, so their figures also timed the page it led
+  to, for B2 and the S3 regions on another host. Chrome opens a new connection
+  for most checks of an S3 region's `/robots.txt`, so those figures now include
+  connection setup and TLS, where they included a request to `aws.amazon.com`.
+  `README.md` says what a figure is: the time until the answer's headers arrive,
+  which includes the server's time to answer, and the DNS lookup, connection
+  setup and TLS whenever the browser opens a new connection
 - 2026-10-26: the six Hetzner targets answer wherever the page is served from
   ([#191](https://git.eeqj.de/sneak/netwatch/issues/191)). They close the
   connection without an answer when the request has a `Referer` header. The