Replace systemIOActor with queued systemIOService

[franknoirot]

Summary

This draft replaces systemIOActor as a public app subsystem with a registry-backed queued systemIOService, then moves the remaining project/session ownership to callers that already own those effects.

• Adds focused project file helpers and a reusable safe file-route transition helper.
• Replaces the XState systemIOActor with a queued service for filesystem requests, shallow local project indexing, status signals, coalescing, and per-resource serialization.
• Moves Home and command palette project data to shallow HomeProjectEntry contributions instead of a recursively scanned global Project[].
• Scopes full Project tree loading to the opened project and Project Explorer refreshes.
• Moves create/import/rename/delete/open flows through explicit service/session calls, with navigation owned by callers.
• Routes MlEphant file patching through the new service.

Why

The current actor was carrying too many responsibilities: filesystem effects, cached project lists, navigation requests, watcher policy, and session state. This splits those concerns so filesystem work can be queued/coalesced independently while route/session code owns route effects and opened-project state.

This is intended to address the concurrency and simplification goals from #12350, and to prepare the route-loader cleanup needed by #12082.

Coordination

Expected to supersede, pending review:

• Add project storage registry service #12378
• Seed registry-owned SystemIO service #12342
• Add project session registry service #12080

#12082 will likely need to be rebased onto this branch once the shape is accepted.

Validation

• npm run lint
• npm run tsc
• npx vitest run --mode=development src/lib/systemIOService.test.ts src/components/layout/areas/ProjectExplorerPane.test.ts src/lib/commandBarConfigs/projectsCommandConfig.spec.ts src/lib/routeLoaderUtils.test.ts src/components/layout/areas/MlEphantConversationPaneWrapper.spec.tsx
• removed-surface scan for systemIOActor, SystemIOActor, SystemIOMachineLogicListener, waitForIdleState, readFoldersFromProjectDirectory, and related legacy exports

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Project	Deployment	Actions	Updated (UTC)
modeling-app	Ready	Preview, Comment	Jul 10, 2026 8:56pm