feat(engine): bump itis-dakota 1.5.11->6.24.7 (Dakota 6.20->6.24) — T16mo rung 2

[JavierGOrdonnez]

What (rung 2 of the engine ladder)

• pyproject.toml: itis-dakota==1.5.11 (Dakota 6.20) → itis-dakota==6.24.7 (Dakota 6.24). The 1.5.x line was renumbered to track Dakota's version.
• uv.lock regenerated.
• Version 0.1.0a3 → 0.1.0a4.

Why 6.24.7 (not 6.24.9)

6.24.7 is the latest 6.24.x that still ships cp311 wheels. 6.24.8+ dropped cp311 (only cp312/cp313/cp314), which would force a Python 3.12 migration of both itis-sumo and mmux_vite. 6.24.7 keeps the Python 3.11 primary (parity with mmux/vite). 6.24.9 is deferred until the 3.12 migration is in scope.

Breakage fixed (SPEC §R5)

6.24.7 still carries the 6.23+ Interface::interface_cache() regression: dakota.environment.study()'s ctor throws IndexError: map::at ("called with nonexistent study!") for itis-sumo's pure data-fit surrogate confs (only import_build_points_file, no interface block) — the cache static map is never populated. This broke all 45 real-Dakota surrogate tests (training, cross-validation, UQ propagation, MOGA, import/export, evaluation).

Fixed in itis-sumo (not waiting on the upstream get-or-create fix): config/funs_create_dakota_conf.py::add_r5_interface_cache_workaround() (appended to every conf via start_dakota_file()) declares an otherwise-unused single model R5_WA_MODEL wired to a no-op fork interface (analysis_drivers='true'), and each surrogate model now points at it via truth_model_pointer='R5_WA_MODEL'. This forces the Interface to be constructed (populating the cache) during study setup; the dummy model is never referenced by any method/iterator, so the interface is never executed. Behavior unchanged.

Verification

• make test (full suite, incl. real Dakota): 318 passed (was 273 passed / 45 failed on 6.24.7 before the shim).
• ruff + ty clean.

Notes / follow-ups

• JSON input seam (SPEC R4) NOT part of this rung (deferred per scope).
• Downstream: mmux_vite must re-pin to itis-sumo==0.1.0a4 and re-run its full CI (next step, rung 2 consumer side).
• SPEC updated: T16mo rung 2 ✓, §B B16mo added, engine/deps/py notes refreshed.