Matrix packages (mautrix-*, matrix-continuwuity) only exist in
nixpkgs-unstable, not in nixpkgs 24.05 stable. This commit updates
all module defaults and references to use pkgs-unstable.
Changes:
- Add pkgs-unstable to module function signatures (4 modules)
- Update package option defaults from pkgs.* to pkgs-unstable.*
- Configure pkgs-unstable in flake.nix to permit olm-3.2.16
- Add VM config permittedInsecurePackages for olm (mautrix dependency)
The olm library is deprecated with known CVEs but required by mautrix
bridges. This is acceptable for testing; production should migrate to
newer cryptography implementations when available.
This maintains our stable base system (NixOS 24.05) while using
unstable only for Matrix ecosystem packages under active development.