PR #13136: a prospect with no conversation says so, in place

PR #13136 at 9d04ccb2b7. Local dev server against the stage table (read-only). Before capture, the prospect's stage name was replaced in the page with the fixture name "Resident One", and the sidebar is cropped out.

Before (main)

The route server-redirected to the prospect page with no notice (/conversation became /leasing/prospects/<id>). That is measured, not pictured, because the prospect page shows stage names.

After

• Checked in the page text: "No conversation yet." and "Go back to the prospect to follow up.", with one "Back to …" link.
• The URL stayed on /conversation, and every link in the content points at the prospect.
• It rendered in about 2.3 s.
• The first capture round also had a "Back to …" button under the copy. It repeated the chevron, so it was removed.