[roster/academy]: improvements for lineup management and academy transfers

[NicoRuedaA]

Problem or opportunity

Description
I have three suggestions to make squad management smoother:
Adding a simple "swap" or "bench" button when clicking on players to easily replace injured ones.
An easy way to assign "Starter" and "Sub" roles when we have two players for the same position (like two Mid laners), without sending anyone back to the academy.
Adding an option to put academy players directly on the transfer list so we can sell youth prospects for extra budget.

Problem it solves
Currently, in this experimental version, taking injured players out of the roster is very confusing. Managing multiple players for one role is tricky because of the UI, and there is no way to monetize academy talent.

Scope

Gameplay

Approval pre-flight

• I searched existing issues and did not find a duplicate.
• I understand maintainers must add status:approved before implementation starts.
• I will branch from development using type/lowercase-slug if this is approved.
• I identified whether this changes docs, release behavior, licensing, or data provenance.

[NicoRuedaA]

by @edwick on discord

[TtvNekix]

Solved - #327