[Feat] add flow chain

[tanut32039]

Fixed: #XXXX

Implementation details

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[Copilot]

Pull request overview

Adds first-class Flow chain support to the relayer by introducing a Flow chain provider/client, Flow remote-signing wallet integration, FKMS protobuf RPCs for Flow signing, and database/config updates needed to track Flow transactions.

Changes:

• Introduce relayer/chains/flow (provider, client, config, Cadence script) plus unit tests and mocks.
• Add Flow wallet adapter + remote signer wiring and register Flow wallet creation in the filesystem store.
• Extend DB schema/model to include packet_timestamp, add Flow chain type, and update config parsing/tests + FKMS proto definitions.

Reviewed changes

Copilot reviewed 29 out of 30 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
relayer/wallet/flow/wallet.go	Flow wallet constructor using BaseWallet + Flow adapter
relayer/wallet/flow/types.go	Defines JSON payload used for remote Flow signing
relayer/wallet/flow/remote_signer.go	Implements FKMS-backed signer calling SignFlow RPC
relayer/wallet/flow/adapter.go	WalletAdapter implementation for Flow (remote-only)
relayer/store/filesystem.go	Registers Flow wallet creation by chain type
relayer/db/types.go	Adds PacketTimestamp to Transaction + constructor param
relayer/db/sql.go	Renames DB handle field and adds packet_timestamp upsert + new “latest success sequence” query
relayer/db/migrations/postgres/00005_add_packet_timestamp.sql	Postgres migration adding packet_timestamp column
relayer/db/migrations/postgres/00004_add_flow_chain_type.sql	Postgres migration adding flow to chain_type enum
relayer/db/db.go	Database interface now returns latest successful sequence
relayer/config/config_test.go	Adds Flow config parsing/loading tests
relayer/config/config.go	Adds Flow chain config decoding support
relayer/chains/xrpl/provider.go	Persists packet_timestamp when creating DB transactions
relayer/chains/types/chain_type.go	Adds ChainTypeFlow and string mapping
relayer/chains/flow/script.go	Adds Cadence transaction template used for relaying
relayer/chains/flow/provider_test.go	Adds Flow provider unit tests
relayer/chains/flow/provider.go	Implements FlowChainProvider relay/query logic + DB persistence + metrics
relayer/chains/flow/config.go	Flow chain provider configuration + factory
relayer/chains/flow/client.go	Flow HTTP client pool + blockchain interactions
relayer/chains/evm/provider.go	Persists packet_timestamp when creating DB transactions
relayer/alert/alert.go	Adds alert topic for Flow script execution failure
proto/fkms/v1/signer_grpc.pb.go	Adds gRPC stubs for SignFlow
proto/fkms/v1/signer.proto	Adds SignFlow RPC, Flow payload types, and FLOW enum
proto/fkms/v1/signer.pb.go	Generated protobuf updates for Flow support
internal/relayertest/testdata/flow_chain_config.toml	Adds Flow chain TOML fixture
internal/relayertest/mocks/signer_grpc.go	Updates FKMS mocks to include SignFlow
internal/relayertest/mocks/chain_flow_client.go	Adds Flow client mock (generated)
internal/relayertest/constants.go	Embeds Flow chain config fixture
go.mod	Adds indirect deps for Flow SDK and transitive requirements
go.sum	Lockfile updates for added dependencies

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[Copilot]

Pull request overview

Copilot reviewed 29 out of 30 changed files in this pull request and generated 7 comments.

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[Copilot]

Pull request overview

Copilot reviewed 30 out of 31 changed files in this pull request and generated 3 comments.

Comments suppressed due to low confidence (1)

relayer/db/sql.go:26

• The NewSQL doc/comment and splitDbPath examples still reference the driver name postgresql, but the implementation only accepts postgres (and the README now documents postgres). As written, a user following the postgresql:... example would hit ErrUnsupportedDriver. Please update the comment/examples to match the actual accepted driver names.

	Db *gorm.DB
}

// NewSQL opens a new Gorm connection using the given driverName and dbPath.
// Supported drivers: "postgresql", "sqlite".
func NewSQL(dbPath string) (SQL, error) {

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