Effect loose ends

Small follow-ups that do not fit neatly into the main facade, route, tool, or schema migration checklists.

Config / TUI

• cli/cmd/tui/config/tui.ts - finish the internal Effect migration. Keep the current precedence and migration semantics intact while converting the remaining internal async helpers (loadState, mergeFile, loadFile, load) to Effect.gen(...) / Effect.fn(...).
• cli/cmd/tui/config/tui.ts callers - once the internal service is stable, migrate plain async callers to use TuiConfig.Service directly where that actually simplifies the code. Likely first callers: cli/cmd/tui/attach.ts, cli/cmd/tui/thread.ts, cli/cmd/tui/plugin/runtime.ts.
• env/index.ts - already uses InstanceState.make(...).

ConfigPaths

• config/paths.ts - split pure helpers from effectful helpers. Keep fileInDirectory(...) as a plain function.
• config/paths.ts - add a ConfigPaths.Service for the effectful operations so callers do not inherit AppFileSystem.Service directly. Initial service surface should cover:
  • projectFiles(...)
  • directories(...)
  • readFile(...)
  • parseText(...)
• config/config.ts - switch internal config loading from Effect.promise(() => ConfigPaths.*(...)) to yield* paths.*(...) once the service exists.
• cli/cmd/tui/config/tui.ts - switch TUI config loading from async ConfigPaths.* wrappers to the ConfigPaths.Service once that service exists.
• cli/cmd/tui/config/tui-migrate.ts - decide whether to leave this as a plain async module using wrapper functions or effectify it fully after ConfigPaths.Service lands.

Notes

• Prefer small, semantics-preserving config migrations. Config precedence, legacy key migration, and plugin origin tracking are easy to break accidentally.
• When changing config loading internals, rerun the config and TUI suites first before broad package sweeps.