Finish the `settings/` slice extraction

[JSONbored]

Problem: Most of ORB's settings-resolution logic is confirmed pure (no D1/Env dependency) and is the lowest-risk, most-precedented extraction target — the engine package already has a working shim/twin convention established for part of this directory.

Area: ORB / gittensory-engine

Proposal: Move the remaining confirmed-pure settings files into gittensory-engine, converting each to a thin re-export shim in src/, following the existing convention exactly. Leave the one confirmed I/O-bound settings file (the one that directly queries the database) behind in src/.

Deliverables:

• The confirmed-pure remainder of src/settings/ moved into gittensory-engine, with working shims.
• The coverage-include configuration updated in the same PR (per the coverage gotcha in the architecture strategy).

Acceptance criteria:

• Every existing test for the moved files still passes unchanged.
• Codecov correctly attributes coverage to the moved files via the shim.

Boundaries:

• Don't move the one file that directly queries the database — it's correctly an adapter, not core logic.

[linear-code]

JSO-3539