Fix RPCError code and add DeleteSector

[peterjan]

Testing data integrity in indexd I noticed the RPCError returned by RPCVerifySector has a wrong code. I also extended the EphemeralSectorStore with a DeleteSector to enable mocking a host that lost it.

[Copilot]

Pull Request Overview

Fix incorrect RPCError code in RPCVerifySector and extend the ephemeral sector store with a deletion method

• Added DeleteSector to EphemeralSectorStore for simulating a lost sector
• Changed RPCVerifySector to return ErrorCodeHostError instead of ErrorCodeBadRequest
• Added a changeset entry for tracking this minor fix

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
testutil/host.go	Implement DeleteSector to remove sectors from the in-memory store
rhp/v4/server.go	Update handleRPCVerifySector to use ErrorCodeHostError
.changeset/fix_rpcerror_code_in_rpcverifysector.md	Add a changeset file documenting the RPC error code correction

Comments suppressed due to low confidence (2)

testutil/host.go:60

• Consider adding unit tests for DeleteSector to cover both successful deletion and the error path when the sector is not present.

func (es *EphemeralSectorStore) DeleteSector(root types.Hash256) error {

rhp/v4/server.go:1110

• Update or add RPC-level tests for handleRPCVerifySector to assert that a missing sector now returns ErrorCodeHostError.

		return rhp4.NewRPCError(rhp4.ErrorCodeHostError, err.Error())