[orian]

Summary

• add override parsing and layer replacement for views, dictionaries, and raw objects
• preserve override in unresolved layer serialization and consume it from resolved schemas for every managed kind
• document the uniform contract across tables, materialized views, views, dictionaries, raw objects, and named collections; nodes remain metadata and database blocks remain merge containers
• add collision, locator, writer, loader integration, and command-level end-to-end coverage

Verification

• go test ./...
• go test -race ./internal/... ./cmd/...
• go vet ./...
• go build ./...
• focused hclexp load end-to-end test composing all six managed object kinds

Closes #231