v1.10.1: Don't assume git in the architecture check

Fix

The ARCHITECTURE CHECK introduced in v1.10.0 told the agent to git mv files unconditionally. Projects that aren't under git — fresh prototypes, downloaded samples, other VCS — would hit a hard failure on a step that has an obvious fallback.

The instruction now reads: git mv if the project is under git (keeps history), a plain move otherwise.

Also removed a redundant git mv aside from the confirm-with-user step; that step is about the change being hard to reverse, not about tooling.

Prompt text only — no behavior or API changes.