Context

Follow-up from #1113 (versioning infrastructure evaluation). These configuration entities were identified as high-value candidates for versioning via the generic VersionSnapshot[T] infrastructure from #1076.

Candidates

EvaluationConfig (HIGH value, TRIVIAL migration)

• Location: src/synthorg/hr/evaluation/config.py
• Why: Scoring framework changes affect all agent evaluations. Audit trail needed for "which config was active when this agent was evaluated?"
• Rollback value: HIGH -- revert to prior scoring methodology
• Change frequency: Low (quarterly/annually)

BudgetConfig (HIGH value, TRIVIAL migration)

• Location: src/synthorg/budget/config.py
• Why: Cost policy changes affect spending behavior. Trace cost spikes to policy changes.
• Rollback value: MEDIUM -- revert quota policies
• Change frequency: Low (every few weeks)

CompanyStructure (HIGH value, MEDIUM migration)

• Location: src/synthorg/core/company.py (ReportingLine, Department, Company)
• Why: Org chart changes are major events. Compliance-critical for approval chain audits ("who was authorized to approve this task?")
• Rollback value: HIGH -- revert org restructuring
• Change frequency: Very low (2-4 times/year)

Implementation

For each candidate:

1. Create <entity>_versions table via SQLiteVersionRepository[T]
2. Wire into persistence backend
3. Use VersioningService[T].snapshot_if_changed() at mutation points
4. Add API endpoint for listing historical configs
5. Tests

Depends on #1131 (WorkflowDefinitionVersion migration validates the pattern).