Use span in PK operations and avoid needless secure_vector #5573

Job	Run time
Windows (shared, x86_64, windows-2022)	11m 37s
Windows (static, x86_64, windows-2022)	7m 2s
Analysis (coverage, gcc, ubuntu-24.04)	9m 52s
Windows (amalgamation, x86_64, windows-2022)	5m 13s
Analysis (sanitizer, msvc, windows-2022, ninja)	17m 1s
Windows (shared, x86, windows-2022)	11m 8s
Analysis (sanitizer, clang, ubuntu-24.04)	13m 57s
Analysis (sanitizer, gcc, ubuntu-24.04)	17m 17s
Analysis (valgrind, clang, ubuntu-24.04)	16m 19s
Clang Tidy	4m 2s
Linux (gcc, shared)	3m 43s
Analysis (fuzzers, gcc, ubuntu-24.04)	8m 41s
Linux (gcc, amalgamation)	4m 0s
macOS (shared, xcode, macos-13)	4m 28s
Analysis (lint, gcc, ubuntu-24.04)	48s
Linux (gcc, static)	6m 12s
macOS (amalgamation, xcode, macos-13)	5m 12s
Analysis (format, gcc, ubuntu-24.04)	23s
Linux (clang, shared)	4m 0s
macOS (shared, xcode, macos-14)	2m 59s
Analysis (limbo, gcc, ubuntu-24.04)	3m 4s
macOS (amalgamation, xcode, macos-14)	2m 37s
Special (examples, gcc, ubuntu-24.04)	2m 46s
Special (minimized, gcc, ubuntu-24.04)	30s
Cross (cross-i386, gcc, ubuntu-22.04)	4m 42s
Special (bsi, gcc, ubuntu-24.04)	1m 56s
Cross (cross-arm32, gcc, ubuntu-24.04)	12m 1s
Special (docs, gcc, ubuntu-24.04)	51s
Cross (cross-arm64, gcc, ubuntu-24.04)	8m 27s
Cross (cross-ppc64, gcc, ubuntu-24.04)	8m 19s
Cross (cross-mips64, gcc, ubuntu-24.04)	8m 32s
Cross (cross-android-arm64, clang, ubuntu-24.04)	2m 29s
Cross (static, gcc, windows-2022, make)	6m 32s
Cross (cross-ios-arm64, xcode, macos-13)	2m 42s
	3h 39m 22s

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