v0.14.7 — PM-side task cancel

Added

• portfolio_cancel_feature — the PM can un-dispatch a task on a team board (#27). The PM could dispatch but never cancel; a stuck or duplicate task had no recovery from the PM side (Roxy's task_close failed with 'unknown issue' — no write path to the team's board). New tool POSTs to the team's project_board /features/{id}/cancel over the stored bearer, moving the feature to the terminal 'cancelled' lane. The managed repo + any PR are untouched. Pairs with the v0.14.6 dispatch dedup for real queue control. (#28)