[Astro-Han]

Summary

After #6655 delegated project rule-file loading to native CLIs, the cancellation test still changed the workspace's AGENTS.md to trigger a Maka instruction update. The update no longer occurred, so the fixture reported opened instead of before_instructions_ack and failed baseline CI.

Create .maka in the fixture's configured instruction home and change .maka/AGENTS.md instead. Keep the existing cancellation, confirmed-digest, native-session identity and retry assertions for Codex, Antigravity and Claude. Production behavior and test timeouts are unchanged.

Refs #6655.

Verification

• Reproduced the original failure locally on rust-preview@72162299fa: expected before_instructions_ack, received opened, matching baseline CI.
• Four focused maka-agent-native library tests passed with cargo nextest: instruction-ack cancellation, all-protocol instruction updates/session reuse, skill instruction replacement/clearing, and global instruction selection/admission. These use local protocol fixtures, not live vendor CLIs.
• cargo fmt --all -- --check and git diff --check passed.
• Strict cargo clippy --locked -p maka-agent-native --tests --no-deps -- -D warnings reported three existing warnings in owner/assistant.rs and owner/tests/session_parent_authority.rs; both files are identical to the base. The same check passed with only clippy::collapsible_if and clippy::needless_borrows_for_generic_args allowed on the command line. No lint configuration was changed.
• Full repository checks were left to CI.

AI use

• No generative tool made a substantive contribution
• Generative tooling made a substantive contribution

Tool(s) and scope: Codex diagnosed the failure, updated the test fixture, ran focused verification and drafted this PR.

Checklist

• Tests cover the change and fail without it
• Format, typecheck and the affected suites pass locally

Formatting and focused tests pass; the strict Clippy baseline exception is described above.

Does this PR entail a change in behavior?

• Yes — described under Summary above
• No