Add CITATION.cff for repository citation metadata #4575

Job	Run time
pre-commit / check-file-sizes	7s
pre-commit / pre-commit	2m 7s
ubuntu / clang-build (ubuntu-24.04)	2m 50s
ubuntu / gcc-build (ubuntu-24.04, Debug)	2m 8s
mac / clang-build (Release)	3m 48s
windows / msvc-build (Release)	5m 33s
mac / clang-build (Debug)	2m 14s
ubuntu / gcc-build (ubuntu-24.04, Release)	2m 21s
windows / clang-build	3m 26s
windows / msvc-build (Debug)	3m 39s
ubuntu / gcc-test (ubuntu-24.04)	8m 26s
ubuntu / clang-sanitizer-build (ubuntu-24.04)	3m 37s
ubuntu / clang-test (ubuntu-24.04)	8m 23s
windows / clang-test	3m 46s
mac / clang-test	5m 10s
windows / msvc-test	5m 19s
ubuntu / clang-sanitizer-test (ubuntu-24.04)	2m 50s
windows / clang-test-extended	4m 30s
ubuntu / clang-sanitizer-test-extended (ubuntu-24.04)	2m 21s
mac / clang-test-extended	3m 3s
windows / msvc-test-extended	3m 1s
ubuntu / gcc-test-extended (ubuntu-24.04)	4m 32s
ubuntu / clang-test-extended (ubuntu-24.04)	4m 31s
ubuntu / gcc-build-codecov	7m 27s
perf / ubuntu-gcc-build-perf-stats	1m 32s
perf / macos-clang-build-perf-stats	1m 45s
pages / build-scoreboard	25s
pages / build-doxygen-xml	18s
pages / build-sphinx	41s
pages / deploy-pages	-1s
	1h 39m 49s

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