fix(evm): resolve account/ethaccount InvokeEVM calls via the Send fallback

[emmanuelm41]

Problem

Messages using the exported EVM method InvokeEVM (method number 3844450837) sent to a plain account actor were parsed as operation type unknown instead of a meaningful method — even when value was transferred.

Reported example tx: bafy2bzacedyutaqjt2zw4kkldcjcj72l5qxll2dnwq3kjm5uzix3fdccetxco (to f03371596, an account actor, ~11.53 FIL).

Note: 3844450837 is a single method — FRC42("InvokeEVM") = go-state-types builtin.MethodsEVM.InvokeContract. The label depends on the recipient actor type, not the method number.

Root cause

The account/ethaccount fallback branch in GetMethodName (added in #292) was unreachable dead code: its guard required GetMethodByActorName(actorName) == actors.UnknownStr, but that function returns a struct for "account" and "ethaccount", so the guard was never satisfied. The method therefore fell through to <unknown>.

The value itself was never lost — block.go's default branch still emits debit/credit ops for value != 0 — so this was a labeling bug, not a balance-reconciliation bug.

Change

• Extract a pure, testable resolveMethodName() / findMethodInActor() seam: look the method number up in the recipient actor's own method set first, then fall back to METHOD_FALLBACK for account/ethaccount exported methods (>= 1<<24).
• METHOD_FALLBACK stays "Send" (unchanged), so these value transfers surface as ordinary Send operations — the behavior the dead branch originally intended.
• Add TestResolveMethodName — the end-to-end GetMethodName-level coverage that was missing and let this bug hide (the prior test only exercised FindMethodNameInAllActors in isolation).

block.go and SupportedOperations are untouched: "Send" is already handled.

evm contract recipients still resolve to InvokeContract → EVM_CALL, unchanged.

Behavior

Recipient actor	method 3844450837 — before	after
evm	EVM_CALL	EVM_CALL (unchanged)
account	unknown	Send
ethaccount	unknown	Send
placeholder	unknown	unknown (see below)

Verification

• gofmt clean, go vet clean, golangci-lint (new-issues vs master) 0 issues
• TestResolveMethodName (7 cases) passes; make test (./rosetta/services) passes

Notes / possible follow-ups

• ethaccount → Send here diverges from beryx, which labels ethaccount InvokeEVM as InvokeContract (it remaps ethaccount→EVM table). Grouped with account for now.
• placeholder recipients still resolve to unknown (not covered by isAccountActorFallback); fil-parser resolves these to InvokeContract. Documented by a test case.