docs: fix incorrect system-contract address and token-type/enum errors in evm and native pages

[theekrystallee]

summary

four factual errors in documentation page bodies, found during the #732 accuracy audit. these are content bugs (wrong code, wrong enum, wrong token type), not frontmatter or link issues. a developer copying the affected snippets would call the wrong system contract or reference a non-existent status code.

bugs

1. ed25519-integration.mdx calls the wrong system contract (highest impact)

evm/differences/native-devs/ed25519-integration.mdx routes the HIP-632 isAuthorized and isAuthorizedRaw calls to address(0x167) (the Hedera Token Service). these functions live on the Hedera Account Service (HAS) at 0x16a. copying this code calls HTS instead of HAS and fails.

• expected: address(0x16a)
• confirmed against evm/development/forking.mdx, the evm/hedera-services/hybrid system-contract table, and the HIP-632 release note in networks/release-notes/services.mdx.

2. native/files/errors.mdx has a truncated status code

the error table lists FILE_CONTENT_EMPT. the canonical protocol enum is FILE_CONTENT_EMPTY (see reference/protobuf/miscellaneous/responsecode.mdx).

3. erc721.mdx mislabels erc-721 as fungible

evm/tokens/erc721.mdx note reads "ERC-721 Token addresses refer to full Hedera Token Service (HTS) fungible token entities." erc-721 is a non-fungible standard; should read "non-fungible token (NFT) entities."

4. erc721-foundry/part1-mint-burn.mdx names the wrong standard

evm/tutorials/advanced/erc721-foundry/part1-mint-burn.mdx says the OpenZeppelin Contracts library "provides a standard and secure implementation of the ERC20 token." this is an erc-721 tutorial; should read "ERC-721 token."

status

fixes are drafted on branch docs/body-bug-fixes-732.