workflow: make next-task context sync impact-scoped

[davidabram]

Summary

Make /next-task task context synchronization proportional to the completed task's verified context impact instead of requiring a whole-root context pass after every task.

The intended behavior is:

• none -> verify the task evidence and return no_context_change without opening unrelated context.
• local -> inspect the nearest authoritative context only.
• domain -> inspect affected domain context; touch context-map.md only when discoverability or ownership changes.
• root -> inspect affected domain context plus only the root files implicated by the change.
• Allow sync to widen or narrow the reported classification only when direct implementation evidence requires it.
• Stop requiring a canonical context entry merely because a task implemented a feature; document durable, non-obvious knowledge instead.
• Keep task synchronization debt (pending | synced | blocked) and retry behavior unchanged.
• Keep whole-repository reconciliation as the responsibility of the explicit audit workflow.

Current state

Draft implementation is on next-task-impact-scoped-sync and updates the generated sce-next-task task-sync and task-execution references consistently across Claude, Pi, OpenCode, and Agents.

The PR intentionally remains draft because the repository's canonical Pkl authoring sources still contain the old unconditional five-root-pass contract. The available GitHub connector exposes whole-file replacement but not a safe patch operation for those large generated-source files, and this environment cannot clone the repository over the network. I have therefore not claimed generation parity or green validation.

Validation still required

• Update config/pkl/base/workflow-context-sync.pkl to make task sync impact-scoped while leaving plan sync unchanged.
• Update both task-execution representations in config/pkl/base/workflow-next-task.pkl.
• Update current-state workflow docs (context/sce/shared-context-code-workflow.md, context/sce/context-workflow-rules.md, context/patterns.md).
• Regenerate target artifacts and confirm parity.
• nix run .#pkl-check-generated
• nix flake check