fix: update static output block to match real CLI progress format

[juhgiyo]

Summary

• Replace aspirational checkmark output in the "Output" section with the real format from TerminalProgressRenderer
• New format shows: Session started, > Delegating to {role}..., ✓ {role} completed ({duration}), ✓ Session complete
• Uses role names (implementer, code-reviewer) instead of activity descriptions
• Durations are realistic (1m 23s, 47s, 2m 34s)
• demo-script.yaml already uses strawpot run — no changes needed there

Closes strawpot/strawpot#510

Test plan

• HTML structure is valid (proper <pre><code> nesting, no broken tags)
• <span class="s"> wrapper preserved around checkmarks for CSS styling
• Whitespace in <pre> block matches the 2-space indent from the real renderer
• Visual: npm run dev and verify the output section renders cleanly

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