Fix workspace file previews

[bkudiess]

Summary

• Route the Workspace page through the read-only agents.workspace.list / agents.workspace.get APIs when the gateway supports full workspace browsing.
• Preserve stable-gateway behavior by falling back to sessions.files.list / sessions.files.get, then the narrow legacy agents.files.* managed-file fallback for older gateways.
• Update stale preview copy and add model tests for all-workspace entries, root parent navigation, pagination truncation, and legacy managed-file fallback request names.

Validation

• .�uild.ps1 — passed
• dotnet test . ests dOpenClaw.Shared.Tests dOpenClaw.Shared.Tests.csproj --no-restore — passed: 2722 passed, 31 skipped
• dotnet test . ests dOpenClaw.Tray.Tests dOpenClaw.Tray.Tests.csproj --no-restore — passed: 1651 passed

Real behavior proof

• Projection proof: WorkspaceFilesModelTests.FromAgentWorkspaceList_MapsAllWorkspaceFilesAsPreviewable verifies agents.workspace.list file rows are previewable even when they are not session-referenced/read/edited.
• Projection proof: WorkspaceFilesModelTests.FromAgentWorkspaceList_MapsAllWorkspaceFilesAsPreviewable verifies empty parentPath remains a root parent path so first-level folders can navigate back up.
• Stable-gateway proof: local gateway 2026.6.11 does not advertise agents.workspace.*; the page now falls back to sessions.files.* first and only then to agents.files.*.
• Not verified / blocked: live full-workspace preview requires a gateway build/channel that supports agents.workspace.list/get; the current stable gateway does not.

Rubber-duck review

Dual rubber-duck review completed before PR creation. Fixed the first five findings: root parent navigation, split list/get capability fallback, missing-file semantics, capability reset on client change, and local search filtering. Also corrected the stable fallback chain to prefer sessions.files.* before agents.files.*.

[clawsweeper]

ClawSweeper status: review started.

I am starting a fresh review of this pull request: Fix workspace file previews This is item 1/1 in the current shard. Shard 0/1.

This placeholder means the worker is alive and reading the current context. I will edit this same comment with the actual review when the claws are done clicking.

Crustacean status: shell secured, claws on keyboard, evidence pebbles being sorted.

[clawsweeper]

Codex review: stale review; fresh review needed.

Summary
The latest durable ClawSweeper review was for head 1686a2ceb1319b2401fd105fcf4d2b5cc6ad5b40, but the PR head is now def36aa995d73b316da61e40d9484ffb5ab87c49. Its old verdict and PR readiness labels are no longer current.

Next step
Run or wait for a fresh ClawSweeper review on the current PR head.

[clawsweeper]

ClawSweeper status: review started.

I am starting a fresh review of this pull request: Fix workspace file previews This is item 1/1 in the current shard. Shard 0/1.

This placeholder means the worker is alive and reading the current context. I will edit this same comment with the actual review when the claws are done clicking.

Crustacean status: shell secured, claws on keyboard, evidence pebbles being sorted.