Enables career-total aggregation by real-world player identity (SbaPlayer)
across all seasons. JOINs StratPlay → Player to access Player.sbaplayer FK,
groups by that FK, and excludes players with null sbaplayer. Also refactors
stratplay router from single file into package and adds integration tests.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
