Create separate entrypoint logic for in-game invoked mode

[emukidid]

Describe the feature

Create a struct, something like:

struct {
    u32 swissMagic, -- something to make it obvious when we're passed this.
    void* readDevice, -- optional
    void* writeDevice, -- optional
    void* screenData, -- ptr to screen dump, more info can be pulled from viRegs perhaps or stored somewhere
    void* reservedAreaBase -- ptr to all our in-game stuff
} swissGlue

Add it as an optional arg to argv, when found, Swiss can skip traditional init and work in a bare-bones mode more akin to an in-game menu of sorts. This could be a separately built version of Swiss or just a separate code path invoked via IGR, it'd have a menu to:

• Current Temperature
• Game Info (time played this session, time played total) (relies on writable device)
• Return to game (relies on a writeable device being present so we could've dumped things Swiss would've overwritten before it invoked itself)
• Dump screenshot
• Save State
• Load State

This would all be much easier on something like the Wii though where we'd just use spare MEM2 to move/mirror the state in.

Add screenshots

No response