Session continuity

Same-runtime reattachment, native resume, new session, and cross-provider context handoff are distinct states. NATIVE_RESUME_UNVERIFIED is not promoted to verified solely because a process starts; the target runtime and resume arguments are checked by the control boundary.

Runtime generations preserve Agent identity and revision lineage. Cross-provider continuation uses a bounded context capsule rather than a foreign provider session identifier.

Current evidence: focused unit/state tests. Real PTY follow-handoff and live provider proof remain unverified.