fix(webapp): ENG-935 close agent pages without a menu entry with experimental.agents off

📝 Description

Follow-up of ENG-929. With experimental.agents off, agent pages that have no menu entry still opened by URL. They are now declared in UNLISTED_AGENT_PATHS and land on Sidecars (admin) or Approvals (others), like the menu-derived paths.

📣 User-facing impact

None (gated behind experimental.agents).

🔗 Related Issue

ENG-935

🚀 Type of Change

• 🐛 Bug fix (non-breaking change which fixes an issue)

📋 Changes Made

• modes/agentPaths.js: UNLISTED_AGENT_PATHS lists /roles/:connectionName/configure, /resource-catalog, /features/runbooks/rules/new, /features/runbooks/rules/edit/:ruleId and /features/runbooks/edit/:connectionId; merged into AGENT_PATHS.
• test/agentPaths.test.js: the listed pages close, and every entry of the list is checked.

🧪 Testing

QA pending.

✅ Checklist

• I have performed a self-review of my own code
• New and existing unit tests pass locally with my changes

📄 Additional Notes

Low risk: flag on, nothing changes.