Require GPUArrays 10.3.1

[ChrisRackauckas-Claude]

Ignore this PR until it has been reviewed by @ChrisRackauckas.

Summary

• remove stale GPUArrays 8 and 9 compatibility
• require GPUArrays 10.3.1 as the oldest supported 10.x release
• retain GPUArrays 11 compatibility

The Julia 1.10 minimum-resolution graph selects GPUArrays 10.3.1 with JLArrays 0.1.3 and ArrayInterface 7.7.0. Earlier GPUArrays 10 releases, plus majors 8 and 9, cannot satisfy the package's current joint dependency graph.

Local verification

• locked Julia 1.10 Core suite at GPUArrays 10.3.1 / JLArrays 0.1.3 / ArrayInterface 7.7.0: passed
• current Julia Core suite at GPUArrays 11.5.8: passed
• current Julia QA group: 20/20 passed
• Runic 1.7.0 check: passed
• git diff --check: passed

No tests were skipped, disabled, or loosened.

[ChrisRackauckas-Claude]

Audit scratchpad:

1. Synced the fork main branch to upstream da7a693 before branching.
2. Reproduced the direct minimum resolver on Julia 1.10. The valid joint graph selected GPUArrays 10.3.1, JLArrays 0.1.3, and ArrayInterface 7.7.0; GPUArrays 8, 9, and earlier 10.x releases are not reachable with the current dependency constraints.
3. Changed only the GPUArrays compat entry in Project.toml.
4. Ran a strict locked Core suite with the direct minimum graph. An initial audit-environment copy omitted the root package weakdeps/extensions metadata and produced an extension-loading failure; I corrected the audit helper, regenerated the environment, and reran from a fresh depot. The corrected run passed all Core files.
5. Ran the current Core suite (passed), current QA group (20/20), Runic 1.7.0, and git diff --check.
6. Confirmed the commit contains the required co-author trailer.

No package tests or assertions were changed.