Web UI: folder names blank in session file tree sidebar

Description

Folder rows in the session's file tree sidebar (the persistent right panel opened via the file-tree toggle, not the diff/review tree) render with no label — only the chevron and icon show. File rows are fine.

Root cause: the directory listing in packages/app/src/workspaces/files/model.tsx derives each node's name with entry.path.split("/").at(-1) ?? entry.path. GET /api/fs/list returns directory paths with a trailing separator (e.g. "src/"), so the split's last segment is "", and ?? entry.path never runs because "" isn't nullish. Every directory node ends up with an empty name.

This is the same symptom as #43666, but a different component. #43835 fixed FileTreeV2 (used in the file browser/diff-review tab) by deriving its label from the path instead of node.name, but it didn't touch the tree loader itself, so the older FileTree component — still used in this sidebar's "Files changed"/"All" tabs — kept showing blank folders.

OpenCode version

v2 branch, HEAD 081eef3b80 (web app / packages/app)

Steps to reproduce

1. Open a session in the Web UI and open the file tree side panel (⌘\).
2. Switch to the "All" tab, or expand any folder under "Files changed".
3. Folder rows show no text, only their chevron/icon. Files show their names normally.

Screenshot and/or share link

Before (bug):

After (fix from the linked PR):

Scrolled further down the same "before" tree — .git here is a plain file (this checkout is a worktree, so .git is a gitdir pointer file, not a directory) and renders fine, while the real directories above it are still blank:

Operating System

macOS (reproduced locally; not OS-specific — it's a path-parsing bug reproducible on any platform)