Hop Agents roster peek to full agent page

[TheGreatAxios]

Summary

• Agents roster detail panel gains an Open CTA that hops to /agents/<slug> via detailPath.
• Keeps the panel as DESIGN quick-peek; does not twin the full agent page.

Closes CL-6875

Test plan

• Unit: selected definition panel offers hop to /agents/<slug>
• Manual: select agent on roster → Open → lands on agent page

[TheGreatAxios]

Fix before merge: Open on the Agents roster uses the display name as the detail-route identity (detailPath(definition.name)). Agent detail paths are keyed by definition id/slug, not a mutable display name. An agent whose name differs from its path id will Open to the wrong or missing page. Use the definition path identity instead.

[TheGreatAxios]

Prior FIX-FIRST on this PR was a false positive: definition.name is the immutable kebab slug, not displayName. Opening via detailPath({ slug: definition.name, id: definition.id }) is correct; swapping to id would recreate CL-6875 because isValidSlug("wfd_*") is false.