docs: align consent and capability claims

[theonly1me]

What changed

• Permit onboarding to reduce a configured source root to one ephemeral presence boolean before content consent.
• Describe Shadowclone as a behavioral clone project and treat evaluation as an instrument until a result is published.
• Add a provider capability matrix covering observation, distillation, live clones, dispatch, and transfer evaluation.
• Document remote-owner profile scope separately from repository action policy, including the git-metadata prerequisite.
• Document edit-to-pin, exact-key rejection, incomplete uninstall behavior, and the current dispatch verification limit.
• Add a chronological design index and a maintained Mermaid architecture diagram.
• Replace exclusive landscape positioning with the capabilities Shadowclone currently combines.

Why

The existing consent rule made useful onboarding branch detection impossible without asking about every provider. Public documentation also claimed an unpublished behavioral result, host-enforced verification, and organization-level isolation that the current implementation does not establish.

How to verify

bun run check