bug: Visual artifact on Agents list row hover in light theme

[vybe]

Summary

On the Agents list page in the light theme, hovering a row produces a dark-blue/black band that covers the row and obscures the row contents (name, status, controls). The hovered row becomes unreadable until the cursor moves away.

Context

Reported during a UI/UX review session — flagged as one of several "visual artifacts on the white theme". This is the most reproducible one: hover any row in the agents list, the row turns dark and the text/controls are no longer legible against it.

Likely cause: a hover-state CSS rule that was authored for the dark theme is leaking into the light theme, or a bg-* class is being applied unconditionally.

Acceptance Criteria

• Reproduce the artifact in a browser on the light theme
• Identify the offending CSS rule / component class
• Fix so the hover state is a subtle row highlight that preserves text contrast in both themes
• Verify the same row in dark theme still looks correct after the fix
• Spot-check other list views (templates, schedules, executions) for the same regression

Technical Notes

• Agents list view: src/frontend/src/views/Agents.vue (or similar)
• Tailwind classes applied at the <tr> / row level are the most likely place to look
• This is one of several "white theme artifacts" reported — fixing this one shouldn't preclude opening follow-up issues if more surface during regression testing