TASK-002A: History Contracts and State Extension

• Status: Ready
• Parent: TASK-002
• Spec: SLICE-002
• Depends on: none

AI Execution Profile

• Model class: Budget or Balanced
• Reasoning effort: Low to Medium

Scope

• add application abstraction for run history storage
• extend canonical app state with a RunHistory collection
• define any supporting application models needed for history loading
• keep LastRunSummary semantics compatible with the existing slice

Copy/Paste Prompt

Implement only TASK-002A: History Contracts and State Extension.

Read first:
- docs/specs/SLICE-002-persistent-run-history.md
- docs/adrs/ADR-001-use-central-app-state-store.md
- docs/adrs/ADR-002-file-backed-run-history-store-before-database-persistence.md
- docs/tasks/slice-002/TASK-002A-history-contracts-and-state-extension.md

Goal:
- Add the application-facing contracts and app state support for persistent run history.

Scope:
- Add a run history storage abstraction in the application layer.
- Extend canonical AppState with a RunHistory collection.
- Preserve compatibility with existing LastRunSummary behavior.
- Add only the minimal supporting types needed for history loading and persistence.

Do not:
- Implement file I/O yet
- Implement workflow integration yet
- Build UI yet

Important:
- Keep the UI out of persistence concerns
- Do not invent alternate summary models if RunSummary already fits