fix: resolve CI failures in pezkuwi-subxt-metadata no_std and pezsp-api doc-tests

- Replace thiserror::Error derive with manual Display + core::error::Error
  impl in pezkuwi-subxt-metadata TryFromError, fixing no_std compilation
  (thiserror v1 does not support no_std)
- Add pezsp-test-primitives as dev-dependency to pezsp-api, fixing 3
  failing doc-tests that import pezsp_test_primitives::Block
- Revert unnecessary features=["std"] on workspace pezkuwi-subxt-metadata dep
- Apply taplo formatting to changed Cargo.toml files

Cargo.lock

@@ -20410,6 +20410,7 @@ dependencies = [
  "pezsp-runtime",
  "pezsp-runtime-interface",
  "pezsp-state-machine",
+ "pezsp-test-primitives",
  "pezsp-trie",
  "pezsp-version",
  "scale-info",