Replace Deep dive alert with copy-to-clipboard

[Hefrock]

Summary

• Replaces the Deep dive button's blocking alert() with a copy-to-clipboard action
• Copies a ready-to-paste prompt built from the pattern's name, description, flow steps (including the loop-back + "Done" terminal for loop:true patterns), and common uses — richer than a one-line ask so a fresh Claude conversation has the same context the reader just saw on the card
• Button label briefly flips to "Copied ✓" (or "Copy failed" if the clipboard write rejects) for ~1.6s as feedback, then reverts to "Deep dive ↗"

Example

Explain the "ReAct loop" AI agent design pattern with a real implementation example.

Context: The model reasons about what action to take, calls a tool, observes the result, then reasons again. The loop continues until the task is complete or a stop condition is met. The backbone of most practical tool-using agents.
Typical flow: Task → Reason → Tool call → Observe → (loop) → Done
Common uses: Research agents, coding assistants, web browsing agents

Test plan

• Verified deepDivePrompt() output for both a plain pattern and a loop:true pattern
• Stubbed navigator.clipboard.writeText in a Playwright test and confirmed the clicked button's copied text exactly matches the generated prompt
• Confirmed the button shows "Copied ✓" immediately after click and reverts to "Deep dive ↗" after the timeout
• No console/page errors

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Generated by Claude Code