feat(runs): surface workflow evolution and migration evidence

[ccarvalho-eng]

Outcome

Operators can identify the workflow definition that governs a run, understand migration history, and safely migrate an eligible paused run to an explicitly retained definition.

Scope

• Show the resolved definition version, definition provenance, compatibility state, and migration history on run list and detail views.
• Surface definition-resolution and migration evidence from Jizoku.inspect_run/2 and Jizoku.explain_run/2 without reconstructing state in Kansoku.
• Add a migration action backed by Jizoku.migrate_run/2 that requires an explicit target version and trusted migration module supplied by host configuration.
• Present validation, stale-state, ineligible-run, and missing-definition failures as actionable operator diagnostics.
• Add an example-app scenario containing an old definition, a retained target definition, and a paused run eligible for migration.

Acceptance criteria

• Run list and detail views display definition version and compatibility state.
• An eligible paused run can be migrated through a confirmation boundary, and the refreshed detail shows durable migration evidence.
• Ineligible, stale, and invalid migration attempts do not mutate the run and explain why they were rejected.
• LiveView and example-app tests cover a successful migration and at least one rejected migration.

Runtime support: agentjido/jizoku#481 and agentjido/jizoku#507.