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

internal/handlers/delivery_result_view_test.go

@@ -158,8 +158,7 @@ func TestHandleSourceLogs_RendersFailedAttempt(t *testing.T) {
 // TestHandleSourceLogs_EscapesResponseBody proves the
 // response body is treated as the untrusted remote content it
 // is. The remote chooses these bytes and the page is rendered
-// inside the operator's authenticated origin, where the
-// application's own CSP allows inline script from 'self'.
+// inside the operator's authenticated origin.
 func TestHandleSourceLogs_EscapesResponseBody(t *testing.T) {
 	t.Parallel()