Phase 0 forced a batch_get_tasks full-fetch across every task just to see
descriptions, which blew past the client's token limit on larger lists.
brief.md lives on disk and has no such limit, so descriptions now render
there directly (fenced with an extended backtick run, indented under the
list bullet, so embedded headings/lists/code fences can't break the task
list's own structure). Phase 0 now treats the brief as the primary source
and only falls back to batch_get_tasks for fields it doesn't carry.
Phase 1 previously asked the user to confirm the absence of duplicates
even when no candidate pair was found. The handler now decides that
itself and moves straight to Phase 2; per-pair questions remain when
at least one candidate exists.