Report proposal errors earlier and more precisely where possible #5478

Job	Run time
Build target wasm32-wasi	1m 7s
Test on Linux	8m 43s
Check ZFuture build on Linux	23s
Test Orchard on Linux	10m 40s
Latest build on ubuntu-latest	1m 43s
Check ZFuture build on macOS	31s
Test NU6 on Linux	8m 45s
Latest build on windows-latest	3m 43s
Check ZFuture build on Windows	2m 59s
Test on macOS	10m 32s
Latest build on macOS-latest	1m 43s
Test Orchard on macOS	14m 47s
Test on Windows	15m 33s
Bitrot check	1m 52s
Clippy (MSRV)	1m 15s
Test Orchard on Windows	17m 51s
Test NU6 on Windows	14m 21s
Clippy (beta)	13s
Code coverage	17m 26s
Intra-doc links	1m 33s
Rustfmt	13s
protobuf consistency	57s
UUID validity	3s
	2h 16m 53s

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