[Issacboy123]

Summary

This PR makes saved subagents available again when their parent session is reopened. Finished children return with their recorded results, and children that were still working return as interrupted so users can decide whether to wake them. Reopening remains passive: it does not call a provider, restart work, replay the original task, or deliver an old result again.

This PR is stacked on feat/persist-subagent-lifecycle, which records child histories, lifecycle snapshots, and captured runtime configuration.

Reasoning

Lazy child-session opening keeps parent restoration passive and prevents startup from replaying work. Binding failures to the affected child preserves valid siblings and exposes actionable warnings through the existing runtime-diagnostic path. Wake-time configuration is selected as one complete unit—captured configuration when fully usable, otherwise current parent configuration—to avoid unsupported combinations of models, thinking levels, tools, and harness state.

Changes

• Restored terminal records and mapped persisted queued or running records to interrupted without starting provider work.
• Validated child identity and leaf references during restoration and isolated missing, corrupt, duplicate, forked, or imported histories without blocking valid siblings.
• Opened saved histories lazily on explicit wake and created wake-only replacement sessions for isolated children without replaying the original task.
• Restored complete captured runtime configuration when usable and applied one complete parent-configuration fallback with a warning otherwise.
• Preserved captured harness revisions through the provider request for restored children.
• Added focused restoration, lazy-wake, replacement, diagnostics, configuration-fallback, fork, and import coverage.

Testing

• node ../../node_modules/vitest/dist/cli.js --run test/suite/subagent-persistence.test.ts test/suite/subagent-services.test.ts test/suite/subagent-registration.test.ts test/suite/agent-session-harness-version.test.ts test/session-manager/fork-branch.test.ts test/session-selector-path-delete.test.ts
• npm run check