Why: S9 acceptance finding 3 — the project settings modal exposed the
host override settings (including the model/key group, masked) to plain
project members; the duties data plane was already permission-enforced,
but the host settings surface had no gate.
Evidence: vitest 34 files / 293 tests pass with the change; tsc reports
no errors in the modified file. Ruling per the acceptance plan P1-B:
the modal entry stays (granted duty managers need the RDM tabs), while
the host override settings group renders only for the project owner or
a system admin; RDM tabs keep their own fail-closed gating.
Impact: ProjectSettingsModal project tab renders an explanatory empty
state for non-privileged viewers; members/duties/matrix tabs unchanged.
Refs: S9 acceptance report P1-B
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