[BUG] Cowork: uploaded context lands in the project mount, not mnt/uploads/

What's wrong

At session start, uploaded context files appear under the project mount (e.g. mnt/<project>/) rather than mnt/uploads/. An agent oriented to look under mnt/uploads/ finds it empty and can waste turns polling for files that already arrived elsewhere.

What should happen

Land uploaded context under mnt/uploads/ as the name implies, or document the actual target so agents orient correctly on the first turn. (Low priority — more an orientation/expectation gap than a functional defect.)

Environment

• Surface: Claude for Desktop (Cowork tab), Claude Code 2.1.156 (Agent SDK 0.3.156), model Opus 4.8, macOS (Darwin 25.5.0), Apple Silicon.

Steps to reproduce

1. Start a Cowork session with uploaded context.
2. Inspect mnt/uploads/ — empty.
3. Find the content under the project mount instead.