Drop 'unsafe-inline' from the Content-Security-Policy (closes #530)

The delete prompts on the webhook page were inline onsubmit handlers.
Each delete form now carries its question in a data-confirm attribute,
which one submit listener in static/js/app.js asks. The three style
attributes became Tailwind classes, with tailwind.css regenerated, and
the x-cloak rule moved to style.css. The policy now sends
script-src 'self' and style-src 'self'.

The browser test now answers a target's delete prompt no and then yes,
and also loads the sign-in page, the webhook list, the settings and
profile pages and the 404 error page under the policy. The README
states the policy as sent.

Model: opus-5-5

templates/event_body.html

@@ -5,7 +5,7 @@
 {{if .Binary}}
 <p class="text-xs text-gray-500">This body is binary ({{.Size}} bytes) and is not shown. <a href="{{.EventURL}}/body" class="btn-small">Download the body</a></p>
 {{else if .Text}}
-<pre class="rounded-md border border-gray-200 bg-white p-2 text-xs text-gray-700 overflow-x-auto whitespace-pre-wrap break-all"{{if .Scroll}} style="max-height: 32rem; overflow-y: auto"{{end}}>{{.Text}}</pre>
+<pre class="rounded-md border border-gray-200 bg-white p-2 text-xs text-gray-700 overflow-x-auto whitespace-pre-wrap break-all{{if .Scroll}} max-h-[32rem] overflow-y-auto{{end}}">{{.Text}}</pre>
 {{if .Cut}}
 <p class="mt-2 text-xs text-gray-500">Showing the first {{.ShownBytes}} of {{.Size}} bytes, unformatted. <a href="{{.EventURL}}" class="btn-small">Show the whole body</a> <a href="{{.EventURL}}/body" class="btn-small">Download the body</a></p>
 {{end}}