Fix: restore the Review file tree

[xIGBClutchIx]

Summary

This restores the Review side panel's All files tree in Pocodex so the current Codex desktop bundle can list workspace files and open them from the tree again.

What changed

• add vscode://codex/workspace-directory-entries handling in the app-server bridge for the Review file tree
• resolve nested directoryPath requests against the selected workspace root, reject escapes outside that root, and return workspace-relative entry paths that match the current bundle contract
• add vscode://codex/read-file-metadata support with the path, isFile, and sizeBytes fields the Review file tab expects before loading file contents
• add focused regression coverage for root and nested workspace directory listings, hidden-file handling, outside-root rejection, and the read-file metadata contract

Root cause

• Pocodex did not implement vscode://codex/workspace-directory-entries, so the current Codex bundle could not populate the All files tree in the Review side panel
• the Review tree also expects workspace-relative entry paths; absolute paths do not build the visible tree correctly
• after the tree could render, clicking a file still failed because Pocodex did not implement vscode://codex/read-file-metadata, so the bundle stopped before calling read-file

Impact

• Review -> All files shows the workspace file tree again in Pocodex
• clicking files from that tree opens their contents again instead of showing Unable to load file
• focused regressions now cover the listing and metadata bridge contracts the current desktop bundle depends on

Validation

• pnpm run check:commit
• pnpm exec vitest run ./test/app-server-bridge-host-data.test.ts ./test/app-server-bridge-workspace.test.ts
• pnpm exec tsx src/cli.ts --dev --listen 127.0.0.1:8798
• live local verification on http://127.0.0.1:8798/ that Review -> All files renders the repo tree and opening README.md no longer shows Unable to load file