Unify installation of Nix-based native modules

Story: As a user, I want dimos run <blueprint> to automatically prepare any native modules in my blueprint, regardless of whether DIMOS was installed via pip or run from a source checkout, so that I can run blueprints without managing native dependencies myself

Provide a shared way to prepare and launch Nix-based native modules across pip installations and source checkouts, without relying on checkout-relative paths.

Reuse local Nix packages or download them from Cachix when available, building from source when needed. Installed releases should use pinned native sources, while development checkouts should reflect local native changes.

Start with the Rust recorder, Livox Mid360, PointLIO, and FastLIO2.

Acceptance criteria:

• Supported modules work from both pip installations and source checkouts.
• Modules share package resolution and preparation logic.
• Preparation runs automatically on first use and is available through an explicit CLI command.

Related: dimensionalOS/dimos#3970.

Synced from DIM-1627 by che

Start at the dimos run <blueprint> flow and trace how the Rust recorder, Livox Mid360, PointLIO, and FastLIO2 native modules are currently prepared in pip installations and source checkouts. Review the related DIM-1627 work, then define shared resolution and preparation entry points; done means all four modules work in both installation modes, prepare automatically on first use, and support an explicit CLI command.