[OMEGA-508] Remove import of non-existing src/context

[glicerico]

Description

lib_omega.metta:27 imports ./src/context, but no src/context* file has ever existed in the repo (the line dates from the initial commit ee74d60). It's the only library Omega import in the three lib files that doesn't resolve. getContext is defined in src/loop.metta:30. The import was silently skipped, so behaviour doesn't change.

How Has This Been Tested?

Loaded lib_omega.metta from current main (1a7624e) on PeTTa v1.0.4 (the version pinned in the Dockerfile), with SWI-Prolog 9.3.36, using a minimal script:

!(import! &self (library lib_import))
!(import! &self (library Omega lib_omega))
!(println! LOADED_OK)

• Before the change: loads, exit code 0.
• After the change: loads, exit code 0. The output is byte-identical to before.
• A second script that queries getContext after loading also gives identical output before and after. getContext comes from src/loop.metta.
• Control: importing a deliberately nonexistent module (./src/definitely_missing_xyz) also loads silently. This confirms the removed line was a no-op.

Test scenario: run the script above with and without the line and compare the output.

Checklist

• PR contains autogenerated code
• Self-review completed
• Test scenarios above are passed with the version of the code from PR