v0.3.2

Copy-to-clipboard on code blocks

Code blocks now have a copy button that appears on hover:

• Language label — shows the detected language (e.g. JAVASCRIPT, PYTHON, CSS)
• One-click copy — copies the raw code text to clipboard via the Clipboard API
• Visual feedback — icon transitions from clipboard → checkmark (green) for 2 seconds
• Smart filtering — Mermaid diagrams and math blocks are excluded (they render visually, not as code)

The button uses a reveal-on-hover pattern to keep the UI clean — invisible by default, fades in when you hover over the code block.