Coordinate combat logging and instrument Mythic+ startup

[tdecroyere]

Summary

• use LibCombatLogging-1.0 when it is already available in the WoW addon environment, without depending on Raider.IO itself
• fall back to WoW's native LoggingCombat API when the library is unavailable
• leave an already-active physical combat log untouched
• skip the bootstrap when logging in directly inside a party/raid instance
• trace the instance/difficulty/map state on the relevant zone and Mythic+ events
• trace LibCombatLogging handles and start/stop callbacks without calling the native logging API just for diagnostics
• retry a rate-limited bootstrap stop after 10 seconds rather than leaving our handle/state half-released

Why

A real failing session showed that the first Mythic+ started while physical combat logging was off and logging resumed only after the run had already begun. The desktop reader/parser cannot recover a CHALLENGE_MODE_START that WoW never wrote.

This change removes a possible ownership conflict from our bootstrap and gives the next failing session enough passive diagnostics to distinguish:

• Raider.IO/library handle never acquired
• library says an addon owns logging while the physical log is absent
• instance difficulty/map information becomes valid only on a later event

No direct dependency on Raider.IO is introduced; the library is capability-detected at runtime.