AI dashboard agent click updates URL but not gen_ai.agent.name filter

[sentry-junior]

Clicking an agent in the AI Agents Overview dashboard updates the URL query param (agent=<name>) but does not update the gen_ai.agent.name filter widget or re-query the page data. The UI remains unchanged despite the URL reflecting the selected agent.

• Surface: AI Monitoring dashboard — AI Agents Overview
• Steps to reproduce:
  1. Open the AI Agents Overview dashboard
  2. Click an agent name in the Traces panel (e.g. plant_expert_agent)
  3. Observe URL updates with agent=plant_expert_agent
  4. UI / gen_ai.agent.name filter widget does not update; data shown is still unfiltered
• Expected behavior (inferred): Selecting an agent should apply the gen_ai.agent.name filter and refresh all widgets accordingly
• Replay evidence: https://sentry.sentry.io/explore/replays/ba2bd4c12d7c4a84827e32d2e5699c87/
• Dashboard reference: https://demo.sentry.io/dashboard/441046/?project=4510034993545216&statsPeriod=30d

Reported by Neil Manvar.

Action taken on behalf of Neil Manvar.

[linear-code]

ENG-7780