Radio show website: light mode fix, headshot, motto update

- Fix hero title/tagline/description text invisible in light mode
- Replace ghost button with accent-bordered outline button for contrast
- Add [data-theme="light"] overrides for hero gradients
- Add Mike Swanson headshot (WebP 11KB + JPEG fallback) to about page and home
- Replace SVG placeholders with real photo (circular crop on about, framed on home)
- Update show motto across all locations

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

projects/radio-show/website/src/pages/index.astro

@@ -9,7 +9,7 @@ import AboutPreview from '../components/home/AboutPreview.astro';
 import SubscribeCTA from '../components/home/SubscribeCTA.astro';
 ---
 
-<BaseLayout title="Home" description="The Computer Guru Show - Technology: Fun and Simple. Your source for making sense of the tech world, hosted by Mike Swanson from Tucson, Arizona.">
+<BaseLayout title="Home" description="The Computer Guru Show - Helping you deal with all of your technology needs while treating you like a person in the process.">
   <HeroSection />
   <LatestEpisodes />
   <FeaturedClassics />