refactor: Split system_service.py — export_manifest CC=39, validate_manifest CC=35

[vybe]

Problem

src/backend/services/system_service.py (713 lines) contains the two highest-complexity functions in the codebase:

Function	CC	Lines
export_manifest	39	~190
validate_manifest	35	~165
configure_permissions	23	~100

These functions have deeply nested conditionals for manifest field handling.

Proposed Solution

1. Extract validation rules into a ManifestValidator class with focused methods:

   • validate_agents(), validate_credentials(), validate_permissions()
   • Each validates one section of the manifest

2. Extract export logic into composable exporters:

   • export_agent() — single agent to manifest dict
   • export_permissions() — permission matrix
   • export_credentials() — credential mapping

3. Extract configure_permissions into services/permission_service.py

Requires Tests First

These functions have no dedicated unit tests. Add tests before refactoring:

• Manifest with all fields populated
• Manifest with minimal fields
• Invalid manifest structures
• Permission configuration edge cases

Acceptance Criteria

• export_manifest CC < 15
• validate_manifest CC < 15
• configure_permissions CC < 15
• Unit tests for all extracted functions
• system_service.py < 400 lines

Source

Refactor audit 2026-03-13

[vybe]

Actualization (2026-03-30)

File is now 713 lines (was unspecified at filing, issue cited CC=39 for export_manifest and CC=35 for validate_manifest). The cyclomatic complexity is likely still high in those two functions. Still valid.

[oleksandr-korin]

Closing as superseded — file-split refactor tickets created en masse on 2026-03-14 from a one-shot complexity scan. The /code-health weekly automation now scores hotspots dynamically and creates better-targeted issues from current churn × complexity, so static "split N-line file" tickets are no longer the right unit of work. The underlying complexity signal will resurface organically if/when it matters. Reference: backlog lean review on 2026-05-28.