refactor: extract mission lifecycle transitions

[jayscambler]

Summary

• extract mission lifecycle transition logic out of MissionManager
• add focused tests for status transitions and verifier-result mapping
• prepare mission workflows for future state-machine work without changing behavior

TDD / DDD / DRY framing

This is the next stacked architectural PR after #652.

Bounded context extracted:

• Mission Lifecycle — status transitions and verifier-driven lifecycle outcomes for missions

Test-first work:

• added lifecycle helper tests first
• implemented pure mission lifecycle helpers
• rewired MissionManager to delegate transition and verifier-error/result mapping

Changes

New module

• ts/src/mission/lifecycle.ts
  • resolveMissionStatusTransition
  • deriveMissionStatusFromVerifierResult
  • buildVerifierErrorResult

New tests

• ts/tests/mission-lifecycle.test.ts

Manager integration

• ts/src/mission/manager.ts
  • delegates status transition semantics to lifecycle helpers
  • delegates verifier error/result lifecycle mapping to lifecycle helpers

Validation

• cd ts && npx vitest run tests/mission-lifecycle.test.ts tests/mission.test.ts tests/mission-execution.test.ts tests/mission-dashboard.test.ts
• cd ts && npm run lint

Follow-up

At this point, the main remaining code-review recommendation is the larger codegen templating redesign (moving more generator logic away from giant inline strings toward template-backed generation). A future XState-style rewrite can build on the explicit generation and mission state/lifecycle modules introduced in this stack.