Repository navigation

Polish upstream-based bilingual README and add release downloads #2

Job	Run time
contract	4m 9s
test-linux-rust (runner, -p webcodex-runner)	2m 9s
test-linux-rust (server, -p webcodex)	2m 44s
test-linux-rust (workspace-crates, -p webcodex-admin -p webcodex-runner-config -p webcodex-core -...	2m 14s
test-linux-tooling	1m 43s
test-windows-runner	0s
test-macos	0s
test-windows-package	0s
test-windows-core	0s
test-windows-arm64	0s
test-linux-arm64	0s
test-windows	0s
test	3s
	13m 2s