Readiness: a check held by a macOS permission prompt says Python is missing #208

Problem

On the Mac mini, the signed build of #201 (361b3c5) said "Install a Python for uv: run "uv python install" in Terminal, then check again." But the Mac has a Python that uv manages, and uv python find passes in 0.07 s from Terminal with the same PATH.

The cause: uv python find looks through every PATH entry. On that Mac, one entry leads to a folder on an external drive. So macOS showed "“Materialize 3D.app” would like to access files on a removable volume." While the prompt waited, the check hit its 5 s limit (CHECK_MS in sidecar/src/agent.ts) and counted Python as missing. After Allow, Check again passed.

So the readiness notice names the wrong fix when macOS holds the check for a permission. Anyone whose PATH reaches an external drive, a network share, or a protected folder sees "Install a Python" for a Python they already have.

Fix

When a toolchain check ends at its time limit, not with a failing exit, the notice should say so. For example: "Checking for Python took too long. macOS may be asking Materialize 3D for permission. Answer it, then check again." Keep "Install a Python for uv" for a check that actually fails.

Test

A sidecar test with a fake uv whose python find hangs. The need it reports names the time limit and the permission prompt, not an install. The existing test, "a check that hangs ends at its limit", covers the timing.