Team memory sync adds scope-aware checks and per-file refusal handling

What

• The team-memory sync system now reports a specific reason when it can't load a shared memory basis, such as the store being empty, unreadable, mismatched, or over a size cap, instead of just failing silently.
• A new account scope is recognized in several sync checks, for example skipping local-write-preservation checks and allowing pulls even when the walk found nothing.
• The check that stops memory files from being written outside their allowed mount directory (an escape check) is now scope-aware, handling user, account, and team scopes differently through a shared helper.
• If the server refuses to save one particular file during a sync, that file is now marked as refused and skipped on retries for a while, while the rest of the sync continues; the file stays local only and its changes will be lost if the machine is recycled. The sync result reports how many files were refused.
• The internal state Claude Code tracks during a sync now includes fields for refused writes and for whether the shared basis is unusable.

Why These changes make multi-device team memory sync more resilient: one problematic file or an unreadable shared store no longer breaks the whole sync, and the system can explain more precisely what went wrong.