feat(exampleSite): bonsai monogram SVG avatar + recapture screenshots

avatar.svg: vermilion circle with kanji 盆 (bon, from 盆栽) in
washi-paper text. exampleSite/hugo.toml updated to reference it.
images/screenshot.png and images/tn.png recaptured against the demo
now showing all 6 working brand+ui icons.

themes/bonsai/exampleSite/hugo.toml

@@ -10,7 +10,7 @@ disableKinds = ["taxonomy", "term", "RSS", "sitemap", "404"]
   name = "Tien Nguyen"
   tagline = "Software engineer · tending small things with care"
   bio = "Building tools, writing code, growing a quiet corner of the internet."
-  avatar = "/images/avatar.jpg"
+  avatar = "/images/avatar.svg"
   themeToggle = false
   footerText = "© 2026 · made with bonsai"
 

themes/bonsai/exampleSite/static/images/avatar.svg

@@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 200 200" width="200" height="200">
+  <circle cx="100" cy="100" r="100" fill="#8b3a2b"/>
+  <text x="100" y="140" font-family="Georgia, 'Hiragino Mincho ProN', 'Yu Mincho', serif" font-size="120" font-weight="600" fill="#f4efe6" text-anchor="middle">盆</text>
+</svg>