Add tournament status and mode filters to GET /api/tournaments

[Stanley-Owoh]

Summary

Add status and mode query param filters to GET /api/tournaments so the frontend can render tournament tabs without client-side filtering.

Changes

src/schemas/tournament.schema.ts

• Added tournamentListQuerySchema — extends the existing offsetPaginationSchema with two optional enum fields:
  • status: UPCOMING | ACTIVE | COMPLETED
  • mode: UP_DOWN | LEGENDS
• Exported TournamentListQuery type

src/routes/tournaments.routes.ts

• Replaced validate(offsetPaginationSchema, "query") with validate(tournamentListQuerySchema, "query") on the list endpoint
• Updated the request handler to destructure status and mode from the validated query
• Filters are applied independently and combined — invalid enum values return a 400 via the existing validate middleware
• Removed the old inline toUpperCase() case-insensitive status filter (validation is now strict through Zod)

README.md

• Documented the two new optional query params with curl examples

Acceptance Criteria

• ?status=ACTIVE returns only active tournaments
• ?mode=LEGENDS returns only legends-mode tournaments
• ?status=UPCOMING&mode=LEGENDS combines both filters
• ?status=INVALID returns 400
• No filters returns all tournaments (backward compatible)

Closes #330