Authority for ownership and boundary decisions: CONTRACT.md. Read that file before changing the host contract, session ownership, context-menu DI, persistence schema, or activation/preview boundaries.

Hosts compose the package through createWorkspaceFileManagerService() and createSession(...). A session owns the shared file-manager data state, shared interaction state, preview flow, and activation flow for one workspace-scoped instance.

Hosts provide backend capabilities through WorkspaceFileManagerHost. The package keeps shared state in logical workspace paths such as /workspace/src/index.ts and does not depend on tuttid, TSH, TACH, VM paths, or host absolute paths.

The session owns search cancellation. It aborts the active host request when a new search replaces it, search state is cleared, or the session is disposed. Hosts that implement search must forward the supplied AbortSignal to their transport; listRecentEntries receives the same optional signal when it is called for recent-location filtering.

This package is intentionally a reusable frontend workspace-domain surface, not only a transport-agnostic data kernel. Shared session orchestration, preview flow, activation flow, and React-facing interaction state may live here when they are part of the reusable file-manager experience across hosts.

The shared surface consumes host-neutral classification and loading lifecycle from @tutti-os/workspace-file-preview. This package owns file-manager-specific activation-target shaping, localized state projection, shared view-model derivation, and the host contract needed to drive those flows so different hosts can integrate primarily by implementing WorkspaceFileManagerHost instead of rebuilding workflow around the shared UI.

The optional React surface persists the adjustable locations-sidebar and details-panel widths on the current device. Restored widths are clamped to the available surface so the central file list keeps its minimum usable width. The locations sidebar can use the space normally reserved for file details when a host hides the details panel, which keeps long location names readable in compact tool-sidebar layouts. In narrow list layouts, the name column keeps a usable minimum width. Starting a locations-sidebar resize preserves the name column's current width so modified-time and size metadata shrink from the first drag movement.

Hosts now provide one app-level i18n runtime and scope it into the file-manager namespace, rather than hand-assembling package-local message objects.

The React surface renders its default archive and folder fallbacks with code-owned @tutti-os/ui-system SVG icon components. Keep the package root free of fallback image imports: browser-conditioned test environments may select a raw image export and then externalize the package for Node execution, which cannot evaluate .png modules. The legacy @tutti-os/workspace-file-manager/assets/workspace-*-fallback.png subpaths remain available to browser consumers that explicitly need the artwork, but the shared runtime does not depend on them.

What stays outside this package is concrete host integration: desktop preload calls, tuttid transport wiring, host absolute paths, import/export/upload flows, share/exposure flows, and other product-specific integration details belong in the owning host adapter. See CONTRACT.md for the full ownership table and non-goals.

Host Reuse Pattern

When another host wants to reuse this package:

Implement WorkspaceFileManagerHost in the consuming host.
Keep host transport, local-file picking, and environment-specific capabilities in that host adapter.
Create one host-level i18n runtime that merges:
- host-owned product i18n resources
- workspaceFileManagerI18nResources
- any other shared package i18n resources needed by the same surface
Scope that runtime into the file-manager namespace with createWorkspaceFileManagerI18nRuntime(...).
Provide resolveContextMenu when using the React surface so blank, directory, and file menus stay host-owned.
Optionally provide renderToolbarTrailingActions for product-owned primary toolbar actions (for example upload) after Refresh.
Override wording in the host runtime when the host intentionally owns the product phrasing; otherwise fall back to the package defaults.

This keeps the package reusable across different hosts without pushing host transport wiring or product wording into the shared package.