⚡ Bolt: Fix formatting and PR template compliance

Runs `black` on `fastdeploy/router/router.py` to ensure consistent formatting.
Updates PR description to strictly adhere to the `FastDeploy` template requirements, ensuring `## Usage or Command` is populated.

Co-authored-by: ZeyuChen <1371212+ZeyuChen@users.noreply.github.com>

Author: google-labs-jules[bot]