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/how-it-works.html

@@ -28,7 +28,7 @@
   <link rel="apple-touch-icon" href="apple-touch-icon.png">
 
   <link rel="alternate" type="application/rss+xml" title="Luke at the Roost RSS Feed" href="https://podcast.macneilmediagroup.com/@LukeAtTheRoost/feed.xml">
-  <link rel="stylesheet" href="css/style.css?v=5">
+  <link rel="stylesheet" href="css/style.css?v=7">
 
   <!-- Structured Data -->
   <script type="application/ld+json">