Epic Games: Fix install command to support both fresh installs and repairs

[szymekx13]

Description:

Currently, the installGame() function always uses the --repair flag, which fails for games that are fetched from legendary JSON.

Problem:

1. Games from manifest (installed) have valid exePath.
2. Games from Legendary (avalaile for download) have empty exePath.
3. Both are treated same way - status always Idle
4. Legendary --repair fails becouse game doesn't exist yest

Example of error:

[Legendary] [Core] INFO: Trying to re-use existing login session...
[Legendary] [cli] ERROR: Game "Among Us" (963137e4c29d4c79a81323b8fab03a40) is not installed!

Proposed solutions:

• Detect game installation status (e.g via manifest or exePath)
• Use legendary install GAME --skip-sdl for not-yet-installed
• Use legendary install GAME --skip-sdl --repair for installed
• Remember about Linux and Windows

After clicking Install/Repair

Related:

• Legendary GitHub
• Legendary commands docs

Acceptance Criteria:

• Games from Legendary (empty exePath) are marked as "not installed"
• Fresh install uses: legendary install GAME --skip-sdl
• Repair uses: legendary install GAME --skip-sdl --repair
• Works on Windows and Linux

Files to modify:

• include/MultiLauncher/EpicProvider.hpp (line 164-184: installGame() function)
• include/MultiLauncher/Game.hpp (GameStatus enum)
• include/MultiLauncher/EpicScanner.hpp (game status initialization)

Design decision:

• Should we have one "Install/Repair" button (smart) or two separate buttons?
• Current UI shows single button, but implementation needs to handle both cases
• Decision: it's up to contributor