test(device_instance): add imu_name ownership ordering regression test

[BANANASJIM]

Summary

• Adds src/test/device_instance_imu_ownership_test.zig with a recording-allocator harness
• The allocator intercepts rawFree calls and records the order of destroy(imu_dev) vs free(imu_name_owned) in a global event log
• Also reads UHID_DESTROY opcode from the pipe write-end to confirm imu_dev.close() actually ran
• Wired into build.zig as an independent b.addTest module (same pattern as supervisor_uhid_routing_test.zig), hooked to test_step
• Added to testing_support in src/main.zig for module graph completeness

Test plan

• zig build compiles cleanly (no errors)
• zig build check-fmt passes
• If deinit body is reordered (free(imu_name_owned) before destroy(imu_dev)), g_log[0] becomes free_imu_name and expectEqual(destroy_imu_dev, g_log[0]) fails
• If imu_dev.close() is skipped, UHID_DESTROY read returns 0 bytes and expect(n >= @sizeOf(u32)) fails

refs: architecture-review-v0.1.4.md finding #9 (option B)

Summary by CodeRabbit

• Tests
  • Added a regression test for device instance IMU ownership and resource cleanup behavior.

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[coderabbitai]

Caution

Review failed

Pull request was closed or merged during review

📝 Walkthrough

Walkthrough

The PR adds a new regression test verifying that DeviceInstance deinit properly cleans up resources in the correct order, specifically testing that a UhidDevice is destroyed before its associated imu_name buffer is freed.

Changes

Cohort / File(s)	Summary
Test Module Registration src/main.zig	Imports new regression test module device_instance_imu_ownership_test into testing_support namespace.
Device Instance Cleanup Test src/test/device_instance_imu_ownership_test.zig	New regression test that constructs a DeviceInstance with owned resources, calls deinit(), and verifies cleanup occurs in the correct order: UhidDevice.close() (via pipe monitoring for UHID_DESTROY message) followed by imu_name buffer deallocation. Uses RecordingAllocator to track and assert allocator events.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• feat(io): Phase 13 Wave 1 — UHID output backend + simulator harness #127: Introduces the UhidDevice.close() and UHID_DESTROY behavior that this test directly exercises and validates.
• fix(supervisor): keep uinput alive across device sleep/wake #114: Modifies DeviceInstance lifecycle management (suspend/resume and file descriptor handling) which interacts with the cleanup sequence this test verifies.

Poem

🐰 A test hops through with careful eyes,
Checking cleanup in the right sequence and size,
UhidDevice first, then memory freed,
Resources dance as the rabbit decreed! 🎀

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main change: adding a regression test for imu_name ownership ordering in DeviceInstance, which directly corresponds to the new test file and the PR's primary objective.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch chore/arch-imu-name-ownership-test

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