feat(run): add support for private CA trust with containerd certs management

[NFRBEZ]

Signed-off-by: Nicolas nicolas.frbezar@decathlon.com

Description of your changes

This PR adds support for mounting a host containerd certs directory into the local development control-plane node created by crossplane project run.

Main changes:

• Added a new --containerd-certs-dir flag to crossplane project run.
• Mounted the provided host directory into /etc/containerd/certs.d when creating a new Kind control plane.
• Updated project run help documentation to clarify:
  • the path must be a containerd certs.d-style directory tree,
  • hosts.toml is optional,
  • _default fallback usage,
  • reference to containerd docs for registry host configuration.

Validation:

• Ran targeted checks on changed packages: go test ./internal/project/controlplane ./cmd/crossplane/project
• Updated command help documentation accordingly.

Closes #97

I have:

• Read and followed Crossplane's contribution process.
• Run ./nix.sh flake check to ensure this PR is ready for review.
• Added or updated unit tests.
• Linked a PR or a docs tracking issue to document this change.
• Added backport release-x.y labels to auto-backport this PR.

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