Integrate the correct default provider direction

[deem0n]

Problem

MiApplication>>defaultProvidersQuery calls allClients. An instance-level override in an existing window does not repair new windows. A tested fix already exists in branch fix-default-providers-query and upstream PR moosetechnology/MooseIDE#1659.

Found during the 2026-09-20 FAMIXNGSQL/Moose 13 compatibility audit.

Implementation scope

Track and review the existing one-line fix and its direction regression test in the deem0n fork; ensure the v3 integration image contains it. Avoid duplicating the implementation or upstream PR.

Implementation PR target: deem0n/MooseIDE, in the deem0n fork first. Keep this issue separate from the other v3.0.0 fixes. The PR must explain the previous failure, resulting behavior, compatibility implications, and actual validation.

Acceptance criteria and tests

Client -> central -> provider fixture distinguishes default client and provider queries; existing application and Butterfly suites; fresh-window verification.

• Regression tests demonstrate the reported problem and pass with the fix.
• Relevant existing tests pass; validation environment and limitations are recorded in the PR.
• A separate implementation PR is linked here and reviewed.
• Integrated v3.0.0 acceptance is verified before this release blocker is closed.

Release

Part of the v3.0.0 milestone. An open PR is not a completed fix; release qualification is tracked separately.

Implementation

deem0n/MooseIDE#3

Combined qualification: #32. The implementation is available for review; this issue remains open until its integrated release acceptance is verified.