[codex] labkit app/test platform rewrite

[Pluze]

Summary

• Rewrites the LabKit app/test platform around official MATLAB build tasks and matlab.unittest/matlab.uitest suites.
• Removes app test backdoors, old custom runner entry paths, and oversized public app entrypoint bodies while preserving public launcher names and app-owned science/export behavior.
• Adds MATLAB Project metadata, project/package dry-run checks, CI split jobs, and diagnostic artifacts for tests, coverage, logs, and GUI traces.

Validation

• matlab -batch "buildtool checkProject" passed.
• matlab -batch "buildtool packageDryRun" passed.
• matlab -batch "buildtool checkStyle" passed; 19 tests, with 0 old runner dependencies, 0 app test backdoors, and 0 oversized entrypoints.
• matlab -batch "buildtool testUnit coverage" passed; 27 unit tests and 44 coverage tests, with HTML/Cobertura artifacts generated.
• matlab -batch "buildtool testIntegration" passed; 17 tests.
• matlab -batch "buildtool test" passed; 44 official non-GUI tests.
• matlab -batch "buildtool testGuiStructural" passed; 13 structural GUI tests.
• matlab -batch "buildtool testGuiGesture" passed; 3 gesture tests.
• git diff --check passed.

Notes

• Interactive GUI workflows still require manual user validation; automated GUI coverage is structural and gesture-focused, not full manual workflow validation.
• GUI gesture CI is intentionally manual/scheduled and non-blocking initially.
• buildtool packageDryRun does not export an .mltbx; it only verifies package boundaries and writes ignored artifacts.
• The remaining private-helper contract inventory is expected debt and stays report-only.