[gemcoder21]

1. WCEthereumTransaction reads value as a hex amount when the request is parsed, so a value that is not a hex number refuses the request there, and every reader takes the parsed amount.
2. decode_transaction_kind takes the value: an approval that also sends coins decodes as a contract call, so the review shows the coins it sends and the predicted balance changes.
3. The dapp simulation and WalletConnect Pay act on that decoded kind instead of their own checks, so simulation::evm::is_approval goes.
4. docs/product/wallet_connector.md gets the matching row.

Supersedes #1622.

Transaction	Result	Test
Approval with no value or 0x0	token approval	test_decode_transaction_kind, test_decode_ethereum_approval_data
Approval with a value	contract call	test_decode_transaction_kind, test_decode_ethereum_transaction_kind_from_payload
No calldata, with a value	transfer	test_decode_transaction_kind, test_decode_ethereum_transaction_kind_from_payload
Value absent, null or 0x	none or zero	test_deserialize_wc_ethereum_transaction
Value that is not hex	request refused	test_deserialize_wc_ethereum_transaction, test_map_send
WalletConnect Pay approval with a value	refused	test_map_approval

Checks: cargo test for primitives, gem_evm, gem_wallet_connect, payment, simulation and gemstone pass; cargo clippy --all-features -D warnings on each, just lint, just format, just check-docs and just check-ffi are clean; just fuzz found nothing in 600 s per target (about 13M runs each for wallet_connect_transaction and wallet_connect_request).