Complete filesystem simplification workstream

docs/internal/workspace.md

@@ -33,13 +33,8 @@ previous-session cache paths remain session-durable and are never redirected
 into run-local output space.
 
 Extraction uses run-local receipt, stderr, and output-root helpers, then
-promotes the validated external bundle to the unique immutable Notarius bundle
-path supplied by `internal/artifacts`. `internal/fileops.PromoteDirectory`
-copies only regular files and directories to a same-filesystem temporary
-sibling. Source traversal uses confined directory handles and identity checks
-so replacing an inspected root, directory, or file is rejected rather than
-followed. The completed tree is atomically renamed without replacing an
-existing destination. Exact physical paths belong in
+validates and renames the external bundle to the unique immutable Notarius
+bundle path supplied by `internal/artifacts`. Exact physical paths belong in
 [Operations](../operations.md#extraction-workflow).
 
 ## Locking
@@ -84,12 +79,12 @@ syntax and exact deletion scope belong in [CLI](../cli.md#clean) and
 - Path model and local store: `internal/artifacts/paths.go`,
   `internal/artifacts/local.go`
 - Run-local materialization: `internal/stage/run_local.go`
-- Immutable bundle promotion: `internal/fileops/directory.go`
+- Immutable bundle installation: `internal/stage/extract.go`
 - Workspace modes: `internal/fileops/modes.go`
 - Cleanup confinement: `internal/fileops/cleanup.go`,
   `internal/app/cleanup_targets.go`, `internal/app/post_publish_cleanup.go`
 - Tests: `internal/artifacts/paths_model_test.go`,
   `internal/artifacts/local_test.go`, `internal/stage/run_local_test.go`,
-  `internal/fileops/directory_test.go`, `internal/fileops/modes_posix_test.go`,
+  `internal/fileops/modes_posix_test.go`,
   `internal/fileops/cleanup_test.go`, `internal/app/cleanup_targets_test.go`,
   `internal/app/post_publish_cleanup_test.go`