[refactor] Reduce Complexity in Upgrade Resumable, Provision Pipeline, and Server Init

[kangeunchan]

Enhancement Description

Refactor key application/daemon hotspots into testable state-machine/pipeline/builder patterns to reduce complexity and improve reliability.

Background

Several core functions mix control flow with business logic and initialization concerns, with high complexity and low/zero test coverage. Refactoring them into explicit patterns (table-driven state machine, pipeline steps, builder) improves reviewability and enables unit testing.

Scope

Refactor upgrade resumable execution to table-driven state machine

Files: internal/application/upgrade/resumable_execute.go

• Replace imperative switch/fallthrough with handler map
• Make state transitions explicit and testable

Decompose provisioning use case into pipeline steps

Files: internal/application/devnet/provision.go

• Extract: prepareMetadata
• Extract: fetchGenesis
• Extract: initializeKeysAndNodes
• Extract: patchGenesis
• Extract: persistState

Refactor daemon server initialization to builder pattern

Files: internal/daemon/server/server.go

• Introduce ServerBuilder with With* methods
• Centralize cleanup in LIFO order using multierr

Non-Goals

• Changing external behavior of upgrade/provision workflows
• Large-scale architecture refactor beyond the affected hotspots
• Redesign of persistence/storage models

Risks and Open Questions

• State machine refactor must preserve resume semantics and persistence behavior
• Pipeline step boundaries may change error propagation; ensure consistent wrapping and context
• Builder pattern must preserve initialization order and lifecycle management

Validation Plan

Unit and Integration Checks

• go test ./... for modified packages
• New unit tests per state handler / pipeline step / builder component
• Verify state transition map covers all prior states and paths

End-to-End Checks

• Run upgrade resume scenarios (resume from each stage if feasible)
• Run provisioning workflow end-to-end for representative networks
• Start daemon and verify core services are available (smoke)

Evidence Required in Issue Updates

• Before/after LOC/complexity summary for each refactored function
• Example state transition diagram or table derived from handler map
• Test output snippets showing coverage for new handlers/steps

Acceptance Criteria

• executeWithGovResumable < 120 LOC and complexity < 15
• ProvisionUseCase.Execute < 100 LOC and complexity < 12
• server.New < 120 LOC and complexity < 10 (or new entrypoint meets target)
• Added unit tests make steps independently testable

Deliverables

• PR implementing table-driven state machine + tests
• PR implementing provisioning pipeline + tests
• PR implementing server builder + lifecycle tests

[kangeunchan]

pull requeset : #104