Add asset capture instructions and sample content for README screenshots

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

.gitignore

@@ -1,6 +1,3 @@
-# Assets (screenshots/GIFs added locally)
-assets/
-
 # Personal therapy data (generated by setup)
 # Note: CLAUDE.md is NOT ignored here - we need it for repo setup instructions
 # The generated therapy folder has its own .gitignore