Drop older SciML major versions from compat

[ChrisRackauckas-Claude]

Please ignore this PR until it has been reviewed by @ChrisRackauckas.

What changed

Pure [compat] edits that drop older major versions of SciML and JuliaSymbolics packages. For each maintained dependency, only the current (non-yanked) major remains; an existing lower bound on that major is kept. No code, tests, or package version were changed.

• Project.toml [deps] PreallocationTools: 0.4, 1.0 → 1.0 (drop 0.4; current major is 1)
• Project.toml [deps] SymbolicLimits: 0.2.2, 1.1 → 1.1 (drop 0.2.2; current major is 1)

Why

JuliaSymbolics is treated as part of the SciML-maintained group for this policy. Supporting multiple majors keeps untested resolver windows. Current majors come from JuliaRegistries/General Versions.toml, ignoring yanked = true releases.

Verification

Not verified here: the full test suite, QA, or a live julia-downgrade-compat run.

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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 23.42%. Comparing base (cf6ebb4) to head (acacfd2).
⚠️ Report is 7 commits behind head on master.
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Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1952   +/-   ##
=======================================
  Coverage   23.42%   23.42%           
=======================================
  Files          61       61           
  Lines        5997     5997           
=======================================
  Hits         1405     1405           
  Misses       4592     4592           

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