Style transcript turns and bump style.css cache version

The renderer emits .transcript-turn and .transcript-speaker, neither of which
had any CSS, so speaker labels and turns rendered unstyled. Extends the
existing .speaker-label rule rather than duplicating it.

Bumps style.css to v=7 everywhere — the file changed, and pages referenced a
mix of v=5 and v=6, so some visitors would have kept a cached copy without the
new rules.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

website/404.html

@@ -15,7 +15,7 @@
   <link rel="icon" type="image/png" sizes="16x16" href="favicon-16.png">
   <link rel="apple-touch-icon" href="apple-touch-icon.png">
 
-  <link rel="stylesheet" href="css/style.css?v=5">
+  <link rel="stylesheet" href="css/style.css?v=7">
   <script defer data-domain="lukeattheroost.com" data-api="/p/event" src="/p/script"></script>
   <script>window.plausible = window.plausible || function() { (window.plausible.q = window.plausible.q || []).push(arguments) }</script>
 </head>