[ClickUp] Add a real URL custom field to AI4UI project lists

[semicolint]

Context

The ClickUp ingestion epic (see related epic issue) intentionally does not populate the applications.url column from list.content. The current Audience: line is not a URL field, and inferring a URL from it would produce bad data.

Proposal

Add a typed URL custom field to the IIDS-AI4UI space (or per-list) named e.g. Production URL so the dashboard sync can populate applications.url cleanly.

Scope of change

• ClickUp: define a new URL-type custom field at the IIDS-AI4UI space level
• One-time manual backfill: set the URL for each active project list (MindRouter 2.0, Nexus, OpenERA, etc.)
• Dashboard ingestion: extend scripts/sync-clickup.ts and the parser to read the new field once it exists

Why now-ish

Low priority — applications.url is NULL-able and the dashboard renders fine without it. File this so we don't lose the thread; pick it up after the main ingestion lands.