Global -q/--queue flag to override the active queue per-invocation
Add a top-level `-q <queue>` / `--queue <queue>` flag (clap `global =
true`) that overrides the per-clone active queue selector for the
duration of one command. Affects every command that reads or writes
the active queue — push/drop/list/swap/rot/tor/prioritize/inbox/
assign/accept/reject/export/queue current/etc. — without changing
the on-disk selector.
Implementation is one process-wide `OnceLock<Option<String>>` set by
`dispatch` from `cli.queue`; `Workspace::queue()` consults it before
reading `<git-dir>/tsk/queue`. No per-command plumbing.
Smoke-tested: `tsk -q tsk queue current` → `tsk`; with active queue
`claude`, `tsk list` lists claude tasks while `tsk -q tsk list` shows
the empty tsk queue.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>