feat: reenable function selectors in txPublicSetupAllowList

[mrzeszutko]

Summary

Re-enables function selector checking in the transaction setup phase allow list. Previously, selector restrictions were removed with the comment "We can't restrict the selector because public functions get routed via dispatch," but the current code already correctly extracts selectors from calldata (calldata[0] contains the target selector). This fix closes a vulnerability where ANY public function on whitelisted contracts/classes was permitted during setup.

• Made AllowedElement require selectors: Removed AllowedInstance and AllowedClass variants — all entries now require both an identifier (address or classId) and a function selector
• Re-enabled selectors in the default allow list with the five traced setup-phase functions: AuthRegistry._set_authorized (private FPC path), AuthRegistry.set_authorized (public FPC path), FeeJuice._increase_public_balance, Token._increase_public_balance, Token.transfer_in_public
• Removed the unnecessary FPC entry — FPC's public functions (_complete_refund, _pay_refund) are set via set_as_teardown(), not enqueued in setup
• Changed config from override to extend: The internal config key is now txPublicSetupAllowListExtend (env var TX_PUBLIC_SETUP_ALLOWLIST unchanged). Defaults are always present; the config only adds entries on top of them
• Added network-json support: The extend list can be distributed via txPublicSetupAllowListExtend in the network config schema
• Replaced isOnAllowList with checkAllowList: Returns a specific rejection reason instead of a boolean. Removed dead branches for selector-less entries. Contract instance is now fetched lazily (only once, only when class-based entries exist). Unknown contracts now return TX_ERROR_SETUP_FUNCTION_UNKNOWN_CONTRACT instead of a generic validation error
• Improved parseAllowList: Requires selectors, rejects unknown type prefixes, handles whitespace
• Added tests: Wrong-selector rejection for both address and class matches, unknown contract rejection, lazy fetch verification, config parsing edge cases

Fixes A-463

[spalladino]

Looks good! On the env var name, let's not rename it for now, but I'm fine keeping the txPublicSetupAllowListExtend name in the rest of the code.

[spalladino]

I know this is old code, but since we're at it: let's have the validator return a TX_ERROR_SETUP_FUNCTION_UNKNOWN_CONTRACT or similar here, instead of throwing and returning a TX_ERROR_DURING_VALIDATION.

[mrzeszutko]

fixed

[mrzeszutko]

@spalladino I reverted the env variable name change, also had to add one more selector due to the failing e2e test