Widen the app page, double its log heights and move the logs (closes #246)

The app page's content column is now at most 84rem wide instead of
56rem (max-w-4xl), set inline because the committed Tailwind CSS has no
class for that width. The build log and container log boxes are 800px
tall instead of 400px. The build log section moves to between the
webhook URL and the environment variables, and the container log
section moves to directly above the deploy key; nothing else moves. A
new handler test renders the app page and checks the width, the section
order and both log heights.
Disclosure: merged after a rebase that changed only TODO.md; the review gated this change on the next before #234, which touches no template.

Model: opus-5-5
Co-authored-by: clawbot <sneak+clawbot@sneak.cloud>

TODO.md

@@ -20,6 +20,11 @@ regress.
 
 # Completed Steps
 
+- 2026-09-29: The app page is 50% wider on large screens (84rem instead of
+  56rem), its build log and container log boxes are twice as tall, the build log
+  sits between the webhook URL and the environment variables, and the container
+  log sits above the deploy key (#246).
+
 - 2026-09-29: A failed build now fails the deploy with the build's own error
   instead of a later "failed to inspect image", and the deployment log shows the
   end of the build output before that error. upaas refuses to build on a Docker