Refactor vault ownership and shared boundaries

[jasonhedman]

Summary

• dissolve the generic manager module by placing vault persistence, domain schemas, workspace configuration, and worker autofill code with their actual owners
• restructure the vault page around colocated section folders and composable section primitives instead of a configuration-driven manager component
• group worker autofill under its worker boundary, remove one-off abstractions, and inline the single-use request schema
• use React Query mutation state directly for model selection and vault mutations, eliminating redundant busy and server-error wiring

Validation

• pnpm check
• pnpm build