Switch to Python 3.14, drop support for Python 3.9 #4412

Job	Run time
pre-commit / check-file-sizes	6s
pre-commit / pre-commit	1m 20s
windows / msvc-build (Debug)	8m 6s
windows / msvc-build (Release)	1m 50s
windows / clang-build	2m 53s
mac / clang-build (Release)	2m 13s
ubuntu / gcc-build (ubuntu-24.04, Release)	2m 23s
ubuntu / gcc-build (ubuntu-24.04, Debug)	2m 3s
ubuntu / clang-build (ubuntu-24.04-arm)	2m 6s
mac / clang-build (Debug)	1m 51s
ubuntu / clang-build (ubuntu-24.04)	3m 4s
ubuntu / gcc-build (ubuntu-24.04-arm, Debug)	1m 39s
ubuntu / gcc-build (ubuntu-24.04-arm, Release)	1m 50s
mac / clang-test	5m 3s
windows / clang-test	2m 42s
windows / msvc-test	4m 55s
ubuntu / clang-test (ubuntu-24.04-arm)	8m 24s
ubuntu / clang-sanitizer-build (ubuntu-24.04)	3m 27s
ubuntu / clang-test (ubuntu-24.04)	8m 23s
mac / clang-test-extended	2m 59s
windows / clang-test-extended	2m 55s
ubuntu / gcc-test (ubuntu-24.04)	8m 26s
ubuntu / gcc-test (ubuntu-24.04-arm)	8m 29s
windows / msvc-test-extended	2m 53s
ubuntu / clang-test-extended (ubuntu-24.04-arm)	4m 29s
ubuntu / clang-test-extended (ubuntu-24.04)	4m 33s
ubuntu / clang-sanitizer-test (ubuntu-24.04)	2m 53s
ubuntu / gcc-test-extended (ubuntu-24.04-arm)	4m 31s
ubuntu / gcc-test-extended (ubuntu-24.04)	4m 30s
ubuntu / clang-sanitizer-test-extended (ubuntu-24.04)	2m 28s
ubuntu / gcc-build-codecov	7m 25s
perf / ubuntu-gcc-build-perf-stats	2m 0s
perf / macos-clang-build-perf-stats	2m 14s
pages / build-doxygen-xml	31s
pages / build-scoreboard	17s
pages / build-sphinx	52s
pages / deploy-pages	-1s
	2h 6m 42s

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