The signing role has two unreconciled sources for the Asset Hub genesis hash

sso_responder::allocate_smart_contract_allowance resolves Asset Hub through features::genesis_for(supported_chains(), AssetHub), the chain the host says it serves. product_manifest::root_manifest resolves it from SigningHostConfig::asset_hub_chain_genesis_hash, the value the embedder configured. Nothing compares them.

A host whose two answers disagree resolves trustedProducts grants against one chain's dotNS registry while allocating PGAS on another. Whoever holds that product name on the other network's registry then decides who may read the victim product's storage.

The split is not accidental. #426 established the configured hash for dotNS reads when usernames moved to Asset Hub dotNS, and #391 established supported_chains() for PGAS because it submits against a chain the host must actually serve. Both conventions are defensible on their own. What is missing is any check that a given host's two values agree, and a decision on which is authoritative when they do not.

Pre-existing on main, independent of #729: pairing_host has 5 config-sourced reads and sso_responder 1 supported_chains read.

An earlier revision of #729 carried a startup warning on divergence. It was removed because it called host FFI code inside the runtime constructor, where a panic aborts the process under the shipping panic = "abort" profile, to emit a warn! that the UniFFI and wasm hosts drop at their default ERROR level. Any detection needs to sit somewhere that does not add a construction-time crash surface.

Start with sso_responder::allocate_smart_contract_allowance, product_manifest::root_manifest, and the SigningHostConfig::asset_hub_chain_genesis_hash and supported_chains() reads; compare how pairing_host uses its five config-sourced reads. Review #426, #391, and the earlier revision of #729 before deciding where divergence detection belongs. Done means the two genesis-hash sources cannot silently authorize different networks, without adding a construction-time crash or ineffective warning.