`basecamp todos update <todo_id> --title "new title"` wipes the existing description

[aleix-cd]

Title-only update silently wipes description

Running basecamp todos update <id> --title "..." clears the todo's existing description, even though --description was never passed.

Why it matters: This is data loss with no warning. The CLI returns {"ok": true, "summary": "Updated todo #..."} and exits 0 while the entire description disappears on Basecamp's side (reproduced with a ~2 KB body). Recovery via the CLI is also broken (see below), so users have to restore manually from a backup in the web UI.

Steps to reproduce:

1. Find a todo with a non-empty description:
   basecamp todos show <id> --json --quiet | jq -r '.description'
2. Update only the title:
   basecamp todos update <id> --title "New title"
3. Re-fetch:
   basecamp todos show <id> --json --quiet | jq -r '.description' → empty string.

Expected: title changes, description preserved.

Actual: title changes, description is now "". The web UI confirms the body is gone. The update response payload itself shows "description": "", which suggests the CLI sends an empty description on every PATCH instead of omitting fields not passed on the command line.

Recovery is also broken in 0.7.2:

basecamp todos update <id> --description "anything" returns {"ok": true, "summary": "Updated todo #<id>"} with exit 0, but updated_at does not advance and description stays empty in show. Reproduced with both a ~2 KB multi-line markdown blob and a one-line value. The PATCH never lands.

Environment: basecamp 0.7.2, macOS (darwin 24.3.0).

Related: #420 (cards update --body silently discards HTML content) — same shape: unspecified fields sent as empty rather than omitted from the PATCH.