Engram 0.15.10

Fixed

• Reuse visualizer project, galaxy and cluster membership during centroid and
  radius calculations, preserving live positions and the existing refresh cadence.
• Align Claude session learner prompts and installer guidance with the privacy
  contract: ordinary work follows configured sharing; explicit private memories
  stay device-local. Automatic updates use authoritative target metadata and
  preserve the target's privacy and project.
• Correct conflicting storage and privacy comments across bundled prompts and
  native tool descriptions.

Diagnostics

• Add optional callback, force preparation and provider-stage timings to the
  existing frame log. Preserve the existing frame and update performance budgets.