add VHS-generated GIFs for all examples

Created tape files and GIFs demonstrating each example:
- counter, timer, list, spinner, views, http
- Updated README with GIF showcase

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

assets/http.tape

@@ -0,0 +1,28 @@
+# HTTP Example
+Output assets/http.gif
+
+Set Shell "bash"
+Set FontSize 16
+Set Width 650
+Set Height 400
+Set Theme "Catppuccin Mocha"
+
+Type "bb http"
+Enter
+Sleep 1s
+
+# Start fetch
+Enter
+Sleep 2s
+
+# Reset
+Type "r"
+Sleep 800ms
+
+# Fetch again
+Enter
+Sleep 2s
+
+# Quit
+Type "q"
+Sleep 500ms