Drop FastGaussQuadrature 0.5 compatibility

[ChrisRackauckas-Claude]

Summary

• remove FastGaussQuadrature 0.5 from the root weak-dependency compatibility range
• make the same change in the isolated AD test environment

FastGaussQuadrature 1.0 has been available since October 2023. Integrals added v1 support in #214 while retaining v0.5; the extension and its AD paths now pass at the exact v1.0 floor, so the superseded pre-1 line no longer needs to constrain resolution.

Local validation

• exact FastGaussQuadrature 1.0.0, Core: 1,741/1,741 passed
• exact FastGaussQuadrature 1.0.0, AD: 2,005 passed plus the suite's 1,176 existing Broken cases; nested AD passed 6/6
• current FastGaussQuadrature 1.3.0, Core: 1,741/1,741 passed
• current FastGaussQuadrature 1.3.0, AD: 2,005 passed plus the same 1,176 existing Broken cases; nested AD passed 6/6
• current QA: 26/26 passed
• Runic 1.7.0 repository-wide check: all 37 Julia files passed

The exact Core run isolated this floor from independent clean-base minimum-resolution defects by using Cubature 1.5.1 and HAdaptiveIntegration 0.2.2 (handled separately in #348 and #349). It also used Moshi 0.3.10 because registered SciMLBase 2.104.0 fails under --depwarn=error with Moshi 0.3.11 and newer; the forward SciMLBase v2 fix is SciMLBase.jl#1451. No tests, assertions, or Broken declarations are changed here.

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

[ChrisRackauckas-Claude]

Validation scratchpad:

1. Reviewed prior art. FastGaussQuadrature support entered through the quadrature extension; bump FastGaussQuadrature v1 #214 added v1 compatibility while retaining 0.5, with no later code path identified that requires the old line.
2. Resolved FastGaussQuadrature 1.0.0 exactly and exercised the extension through the complete Core group: 1,741/1,741 passed.
3. Exercised the isolated AD environment with FastGaussQuadrature 1.0.0: 2,005 passed, the suite's existing 1,176 Broken cases were reported unchanged, and nested AD passed 6/6.
4. Repeated Core and AD with current FastGaussQuadrature 1.3.0: Core passed 1,741/1,741; AD reported the same 2,005 pass + 1,176 existing Broken, then nested AD passed 6/6.
5. Ran current QA: 26/26 passed.
6. Ran Runic 1.7.0 over all 37 Julia files: clean.

For exact Core isolation, the manifest also used the separately corrected Cubature 1.5.1 (#348) and HAdaptiveIntegration 0.2.2 (#349) floors. Moshi was diagnostically pinned to 0.3.10 because registered SciMLBase 2.104.0 has a clean-base forced-deprecation mismatch with Moshi 0.3.11+; SciMLBase.jl#1451 fixes that forward. This PR changes no test code or assertions.

[ChrisRackauckas-Claude]

Post-timer CI follow-up:

• All 11 hosted checks pass.
• The Julia 1.10 Core downgrade job passes.
• Core passes on Julia LTS, release, and prerelease; AD, QA, docs, Runic, Runic Suggestions, and typos also pass.
• GitHub reports the draft PR mergeable with a clean merge state.

No CI follow-up changes are needed.