Update QA for SciMLTesting 2.4

[ChrisRackauckas-Claude]

Summary

• Require registered SciMLTesting 2.4 in the root and QA environments.
• Remove the obsolete QA [sources] path and redundant strict-default flags.
• Replace the dynamic facade escape with a fixed 205-name intentional-reexport snapshot and a concrete 197-name non-module rendered-doc exception. New public reexports and all package-owned public API remain subject to the default SciMLTesting 2.4 checks.

Ignore until reviewed by @ChrisRackauckas.

Local validation

• Registered SciMLTesting resolved as 2.4.0.
• Strict QA: 21/21 passed.
• GROUP=Everything Pkg.test(): Core 17/17; QA 21/21; passed.
• Workspace Runic check passed.
• git diff --check passed.
• No manifests, [sources], workspace paths, or temporary artifacts remain.