Integration tests (git + OCI)

[johnnyhuy]

Summary

• Add integration tests for git and OCI installs.

Context

• End-to-end coverage ensures install/update flows are reliable.

Scope

• Use local fixtures for git sources.
• Use a test OCI registry (or mock server) for OCI sources.
• Validate add, check, and update flows.

Out of scope

• Authenticated registry tests.

Acceptance criteria

• Integration tests pass in CI on Linux.