Repository navigation

feat: parallelize reading manifests #224

Job	Run time
Meson SigV4 (AMD64 Ubuntu 24.04)	7m 26s
AWS (Ubuntu 24.04, S3 + SigV4, bundled AWS SDK)	20m 7s
AWS (Ubuntu 24.04, S3 + SigV4, system AWS SDK)	18m 57s
AWS (macOS 26 ARM64, S3, bundled AWS SDK)	15m 25s
	1h 1m 55s