Add tools to Yahoo Sports

I run a personal head-to-head NFL fantasy league and want to query my team/league data through an AI agent (Claude). Minimum viable tool set:

Get user's leagues — list the leagues/teams tied to the authenticated Yahoo account for a given game (nfl) and season, so the agent can resolve which league/team_key to use.
Get league standings — team records, points for/against, rank, for a given league_key.
Get league settings — roster positions, scoring type, waiver rules, playoff weeks, trade deadline.
Get team roster — current roster for a given team_key, including starters vs. bench, injury/status tags (O, Q, IR), and position eligibility.
Get matchups — head-to-head matchup results/projections for a given week, both my team and opponents.
Get player stats — season and weekly stats for a specific player (for start/sit and waiver decisions).
Get free agents / waiver wire — available players in the league, filterable by position, sortable by ownership % or rank.
Get transactions — recent adds/drops/trades league-wide, so the agent can flag opponent moves.

Read-only access is sufficient — I don't need write/roster-move actions, just visibility to answer questions about my team and the league.

Start by reviewing the repository's existing API integrations and tool entry points, then determine how Yahoo Sports authentication and read-only access fit the project. Implement and verify the requested league, roster, matchup, player, waiver, and transaction queries, with the issue's listed data as the completion checklist.

Written by the indexing model from the issue text.