Drop StaticArrays 0.12 compatibility

[ChrisRackauckas-Claude]

Summary

• remove the obsolete StaticArrays 0.12 test compatibility line
• require StaticArrays 1 for PolyChaos's static-array test coverage

StaticArrays 1.0 was released in 2020, and PolyChaos already exercises the relevant static vector and matrix cases against that API. This only changes a test dependency compatibility bound; package runtime dependencies and public API are unchanged.

Local validation

• locked test environment with StaticArrays v1.0.0: all 16 Core files passed (20,522 tests)
• current test environment with StaticArrays v1.9.18: all 16 Core files passed (20,522 tests)
• GROUP=QA julia +1.10 --project=. -e 'using Pkg; Pkg.test()'
• julia --project=../../runic_env -e 'using Runic; exit(Runic.main(["--check", "."]))'

The stochastic inverse-transform sampling assertion has a separately reproduced clean-master seed-dependent failure. This PR does not alter or suppress that test; its root cause is being investigated independently.

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

[ChrisRackauckas-Claude]

Validation scratchpad:

1. Reviewed the compatibility history. PolyChaos added StaticArrays 1 support in 2020 while retaining 0.12; a later bulk compatibility restoration reintroduced the current 0.12, 1.0 declaration, with no code path identified that requires 0.12.
2. Confirmed the dependency is test-only and that the Core suite contains static vector and matrix coverage.
3. Resolved a locked environment with StaticArrays v1.0.0 and ran all 16 Core test files: 20,522/20,522 passed.
4. Resolved a current environment with StaticArrays v1.9.18 and ran the same 16 Core files: 20,522/20,522 passed.
5. Ran the declared QA group against the current environment: 17/17 passed.
6. Ran Runic in check mode across the repository: clean.

The inverse-transform sampling test is stochastic. A seed-dependent failure has been reproduced separately on clean master; no assertion, tolerance, or test configuration is changed here. That clean-base investigation is proceeding independently.

[ChrisRackauckas-Claude]

Post-timer CI review: all 10 checks completed successfully, including downgrade, Core on Julia LTS/current/pre, QA, documentation, Runic, Runic suggestions, and spelling. The PR remains mergeable and up to date.