ci: add downgrade-compat + adjust lower bounds

[MilesCranmerBot]

Adds a julia-downgrade-compat workflow and bumps a few compat lower bounds to the true minimums required by the current code + test environment.

Locally verified on Julia 1.10 with downgrade-generated Manifest and allow_reresolve=false.
Fork CI green before opening upstream.

[github-actions]

Benchmark Results (Julia v1)

Time benchmarks

	master	3c47609...	master / 3c47609...
eval/ComplexF32/evaluation	6.92 ± 0.5 ms	6.91 ± 0.47 ms	1 ± 0.099
eval/ComplexF64/evaluation	10.3 ± 0.77 ms	10.2 ± 0.91 ms	1 ± 0.12
eval/Float32/derivative	11.1 ± 1.8 ms	11.2 ± 1.8 ms	0.996 ± 0.23
eval/Float32/derivative_turbo	11.1 ± 1.9 ms	11.2 ± 1.8 ms	0.993 ± 0.23
eval/Float32/evaluation	2.48 ± 0.26 ms	2.49 ± 0.26 ms	0.996 ± 0.15
eval/Float32/evaluation_bumper	0.606 ± 0.019 ms	0.603 ± 0.018 ms	1 ± 0.043
eval/Float32/evaluation_turbo	0.54 ± 0.037 ms	0.546 ± 0.038 ms	0.988 ± 0.096
eval/Float32/evaluation_turbo_bumper	0.602 ± 0.016 ms	0.601 ± 0.017 ms	1 ± 0.039
eval/Float64/derivative	14.3 ± 3.5 ms	14.6 ± 2.5 ms	0.983 ± 0.29
eval/Float64/derivative_turbo	14.4 ± 3.6 ms	14.4 ± 2 ms	1 ± 0.29
eval/Float64/evaluation	2.91 ± 0.3 ms	2.86 ± 0.3 ms	1.02 ± 0.15
eval/Float64/evaluation_bumper	1.26 ± 0.046 ms	1.26 ± 0.044 ms	1 ± 0.051
eval/Float64/evaluation_turbo	1.04 ± 0.066 ms	1.03 ± 0.061 ms	1.01 ± 0.087
eval/Float64/evaluation_turbo_bumper	1.27 ± 0.045 ms	1.27 ± 0.043 ms	0.999 ± 0.049
utils/combine_operators/break_sharing	0.0419 ± 0.0013 ms	0.0409 ± 0.00097 ms	1.03 ± 0.041
utils/convert/break_sharing	28.2 ± 3.7 μs	27.9 ± 3.3 μs	1.01 ± 0.18
utils/convert/preserve_sharing	0.102 ± 0.01 ms	0.101 ± 0.0097 ms	1.01 ± 0.14
utils/copy/break_sharing	28.8 ± 3.9 μs	27.8 ± 3.4 μs	1.04 ± 0.19
utils/copy/preserve_sharing	0.0996 ± 0.0097 ms	0.1 ± 0.0099 ms	0.992 ± 0.14
utils/count_constant_nodes/break_sharing	13.6 ± 1.6 μs	12.3 ± 0.81 μs	1.11 ± 0.15
utils/count_constant_nodes/preserve_sharing	0.0858 ± 0.0084 ms	0.0834 ± 0.0047 ms	1.03 ± 0.12
utils/count_depth/break_sharing	14 ± 1.3 μs	13.5 ± 1.7 μs	1.04 ± 0.16
utils/count_nodes/break_sharing	12.7 ± 1.1 μs	12.5 ± 0.71 μs	1.02 ± 0.1
utils/count_nodes/preserve_sharing	0.0863 ± 0.0082 ms	0.0846 ± 0.0061 ms	1.02 ± 0.12
utils/get_set_constants!/break_sharing	0.0334 ± 0.0042 ms	0.0329 ± 0.0037 ms	1.02 ± 0.17
utils/get_set_constants!/preserve_sharing	0.177 ± 0.013 ms	0.171 ± 0.01 ms	1.03 ± 0.097
utils/get_set_constants_parametric	0.0462 ± 0.0057 ms	0.0451 ± 0.0044 ms	1.02 ± 0.16
utils/has_constants/break_sharing	7.99 ± 1.2 μs	7.84 ± 0.72 μs	1.02 ± 0.18
utils/has_operators/break_sharing	2.69 ± 0.26 μs	2.71 ± 0.12 μs	0.989 ± 0.11
utils/hash/break_sharing	24.4 ± 2 μs	23.9 ± 1.5 μs	1.02 ± 0.11
utils/hash/preserve_sharing	0.0993 ± 0.0057 ms	0.0992 ± 0.0063 ms	1 ± 0.085
utils/index_constant_nodes/break_sharing	29.4 ± 3.1 μs	28.9 ± 2 μs	1.02 ± 0.13
utils/index_constant_nodes/preserve_sharing	0.0994 ± 0.0048 ms	0.0999 ± 0.0061 ms	0.995 ± 0.077
utils/is_constant/break_sharing	8.69 ± 1.6 μs	7.29 ± 0.78 μs	1.19 ± 0.25
utils/simplify_tree/break_sharing	31.3 ± 1.6 μs	0.0318 ± 0.0015 ms	0.984 ± 0.068
utils/simplify_tree/preserve_sharing	0.118 ± 0.01 ms	0.111 ± 0.0048 ms	1.07 ± 0.1
utils/string_tree/break_sharing	0.455 ± 0.03 ms	0.44 ± 0.021 ms	1.03 ± 0.084
utils/string_tree/preserve_sharing	0.556 ± 0.028 ms	0.54 ± 0.025 ms	1.03 ± 0.071
time_to_load	0.169 ± 0.0042 s	0.176 ± 0.0035 s	0.963 ± 0.031

Memory benchmarks

	master	3c47609...	master / 3c47609...
eval/ComplexF32/evaluation	0.987 k allocs: 2.53 MB	0.972 k allocs: 2.49 MB	1.02
eval/ComplexF64/evaluation	1.01 k allocs: 5.12 MB	1 k allocs: 5.11 MB	1
eval/Float32/derivative	4.67 k allocs: 17.6 MB	4.67 k allocs: 17.6 MB	1
eval/Float32/derivative_turbo	4.68 k allocs: 17.6 MB	4.6 k allocs: 17.3 MB	1.02
eval/Float32/evaluation	0.978 k allocs: 1.27 MB	0.978 k allocs: 1.27 MB	1
eval/Float32/evaluation_bumper	0.303 k allocs: 0.393 MB	0.303 k allocs: 0.393 MB	1
eval/Float32/evaluation_turbo	0.975 k allocs: 1.27 MB	0.975 k allocs: 1.27 MB	1
eval/Float32/evaluation_turbo_bumper	0.303 k allocs: 0.393 MB	0.303 k allocs: 0.393 MB	1
eval/Float64/derivative	4.8 k allocs: 0.0351 GB	4.78 k allocs: 0.035 GB	1
eval/Float64/derivative_turbo	4.8 k allocs: 0.0351 GB	4.79 k allocs: 0.035 GB	1
eval/Float64/evaluation	0.987 k allocs: 2.53 MB	0.993 k allocs: 2.54 MB	0.994
eval/Float64/evaluation_bumper	0.303 k allocs: 0.771 MB	0.303 k allocs: 0.771 MB	1
eval/Float64/evaluation_turbo	0.987 k allocs: 2.53 MB	0.987 k allocs: 2.53 MB	1
eval/Float64/evaluation_turbo_bumper	0.303 k allocs: 0.771 MB	0.303 k allocs: 0.771 MB	1
utils/combine_operators/break_sharing	4 allocs: 0.953 kB	4 allocs: 0.953 kB	1
utils/convert/break_sharing	2 k allocs: 0.123 MB	2 k allocs: 0.123 MB	1
utils/convert/preserve_sharing	2.4 k allocs: 0.192 MB	2.4 k allocs: 0.192 MB	1
utils/copy/break_sharing	2 k allocs: 0.123 MB	2 k allocs: 0.123 MB	1
utils/copy/preserve_sharing	2.4 k allocs: 0.192 MB	2.4 k allocs: 0.192 MB	1
utils/count_constant_nodes/break_sharing	4 allocs: 0.953 kB	4 allocs: 0.953 kB	1
utils/count_constant_nodes/preserve_sharing	0.404 k allocs: 0.0696 MB	0.404 k allocs: 0.0696 MB	1
utils/count_depth/break_sharing	4 allocs: 0.953 kB	4 allocs: 0.953 kB	1
utils/count_nodes/break_sharing	4 allocs: 0.953 kB	4 allocs: 0.953 kB	1
utils/count_nodes/preserve_sharing	0.404 k allocs: 0.0696 MB	0.404 k allocs: 0.0696 MB	1
utils/get_set_constants!/break_sharing	0.898 k allocs: 25.2 kB	0.898 k allocs: 25.2 kB	1
utils/get_set_constants!/preserve_sharing	1.7 k allocs: 0.138 MB	1.7 k allocs: 0.138 MB	1
utils/get_set_constants_parametric	1.42 k allocs: 0.0663 MB	1.42 k allocs: 0.0663 MB	1
utils/has_constants/break_sharing	4 allocs: 0.203 kB	4 allocs: 0.203 kB	1
utils/has_operators/break_sharing	4 allocs: 0.203 kB	4 allocs: 0.203 kB	1
utils/hash/break_sharing	0.104 k allocs: 2.52 kB	0.104 k allocs: 2.52 kB	1
utils/hash/preserve_sharing	0.504 k allocs: 0.0711 MB	0.504 k allocs: 0.0711 MB	1
utils/index_constant_nodes/break_sharing	2.1 k allocs: 0.094 MB	2.1 k allocs: 0.094 MB	1
utils/index_constant_nodes/preserve_sharing	2.5 k allocs: 0.163 MB	2.5 k allocs: 0.163 MB	1
utils/is_constant/break_sharing	4 allocs: 0.203 kB	4 allocs: 0.203 kB	1
utils/simplify_tree/break_sharing	0.104 k allocs: 2.52 kB	0.104 k allocs: 2.52 kB	1
utils/simplify_tree/preserve_sharing	0.504 k allocs: 0.0711 MB	0.504 k allocs: 0.0711 MB	1
utils/string_tree/break_sharing	11.9 k allocs: 0.999 MB	11.9 k allocs: 0.999 MB	1
utils/string_tree/preserve_sharing	12.3 k allocs: 1.07 MB	12.3 k allocs: 1.07 MB	1
time_to_load	0.145 k allocs: 11 kB	0.145 k allocs: 11 kB	1

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 59.33%. Comparing base (bc05728) to head (3c47609).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #164   +/-   ##
=======================================
  Coverage   59.33%   59.33%           
=======================================
  Files          30       30           
  Lines        2673     2673           
=======================================
  Hits         1586     1586           
  Misses       1087     1087           

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