Add experimental Crimson Desert support

[Benniphx]

Adds Crimson Desert as an Amethyst game using CDUMM for archive-aware deployment.

Amethyst handles profiles and Nexus metadata. CDUMM handles snapshot, import, apply, and restore because Crimson Desert mods patch PAZ/PAMT archives instead of deploying files directly.

Includes:

• Steam and Nexus metadata plus game artwork
• profile order and enabled-state synchronization
• snapshot, apply, restore, and post-apply validation
• rejection of invalid or stale mappings

Tested on Crimson Desert 2.00.01 with Nexus mod 3211. Apply, in-game behavior, restore, and redeploy were verified.

CDUMM is currently an external runtime. Packaging and versioning it still needs agreement before this can be merge-ready.

Related: #404

[Benniphx]

@ChrisDKN Before I take this out of draft, I would like your view on the integration boundary. Crimson Desert requires archive-aware patching, so the current implementation uses CDUMM as an optional external backend.

Would that approach be acceptable if Amethyst:

• requires a known-compatible CDUMM version,
• uses only a stable CLI rather than CDUMM database internals, and
• reports a clear error when the backend is missing or incompatible?

Alternatively, would you prefer the archive handling to live inside Amethyst or be packaged with it? I can follow your preferred direction before marking the PR ready for review.