fix(sessions): auto-update other clients when a session is renamed

[anuj7511]

Summary

Renaming a session did not emit a live update on the CDC/SSE event stream.
RenameSession updates only display_name (+ updated_at), but the
sessions_cdc_update trigger's WHEN guard did not include display_name,
so the update wrote no change_log row — and therefore no session_updated
event ever reached GET /api/v1/events.

Root cause

The trigger (introduced in 0001, later extended by 0017/0019) fires only
when one of the watched columns changes:

WHEN OLD.activity_state    <> NEW.activity_state
  OR OLD.is_terminated     <> NEW.is_terminated
  OR (OLD.first_signal_at IS NULL AND NEW.first_signal_at IS NOT NULL)
  OR OLD.preview_url       <> NEW.preview_url
  OR OLD.preview_revision  <> NEW.preview_revision

display_name is not in that list. Migrations 0017 and 0019 added the
preview_* columns to this same trigger for exactly this fan-out reason;
rename was left out.

Impact

The initiating desktop window happens to refetch on its own (the sidebar
invalidates its workspace query after a successful rename), which masks the
bug there. But any client relying on the CDC stream keeps showing the old
name until an unrelated event forces a refetch — e.g. a second desktop
window, the Connect Mobile client, or every connected client when the
rename comes from ao session rename (which does no client-side invalidation).

Fix

New migration 0024_session_rename_cdc.sql drops and recreates
sessions_cdc_update with OR OLD.display_name <> NEW.display_name added to
the guard and displayName added to the JSON payload (mirroring how
previewUrl/previewRevision are carried). display_name is NOT NULL, so a
plain <> comparison is complete. Per the repo's hard rule I added a new
migration rather than editing a merged one; the Down reverts to the 0019
trigger.

Reproduction

1. Start the daemon and open an SSE reader against GET /api/v1/events
   (e.g. curl -N http://127.0.0.1:3001/api/v1/events).
2. Rename a session via the sidebar or ao session rename <id> <name>.
3. Before: no frame appears on the stream. After: a session_updated
   frame is delivered with the new displayName.

[somewherelostt]

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• @neversettle17-101
• @somewherelostt

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