test(sync): preserve Edge selected-CG lifetime and restart invariants

[branarakic]

Outcome

Preserve the Edge selected-Context-Graph lifetime and restart acceptance scenarios from the retired M1 stack against today's subscription, selected-bootstrap, and recovery architecture.

This is an acceptance-first issue. Implement code only for scenarios that fail on current canary.

Current policy to preserve

• always-on intent is durable and must resume after restart.
• on-demand member intent remains process-local but keeps its live state for the process lifetime; the retired fix(sync): make Edge on-demand synchronization point-in-time #2045 point-in-time detach semantics are not being revived.
• Broad sync disabled must not silently expand a selected Edge into all-CG/system-graph synchronization.
• Authorization denial must remain distinguishable from local backpressure/deferral.

Related current work:

• Add rolling activation for rehydrated context graph subscriptions #1550 covers bounded rolling activation of rehydrated subscriptions.
• Reconnect-triggered background sync amplification can starve foreground catch-up #2052 covers background reconnect amplification.

Scenarios to preserve

1. A configured/durably saved always-on selection enters bounded VM and SWM recovery on first boot; a second restart is not required.
2. After restart, the same selection resumes both finalized VM and live/shared-memory recovery while broad sync remains disabled.
3. Runtime-only and on-demand selections are not promoted into durable periodic work.
4. Removing or demoting a subscription while work is in flight invalidates later phases and prevents stale readiness/progress commits.
5. With broad sync enabled, ordinary system/configured scope remains intact; the narrow selected path must not accidentally replace it.
6. A pure authorization denial wins over local admission deferral in user-facing readiness.
7. Evidence/status schema changes remain backward compatible or receive an explicit version bump.

Acceptance criteria

• Each scenario has a focused current-canary test using production wiring rather than private prototype stubs where practical.
• A real first-boot/restart gate proves exact VM and SWM outcomes for one selected graph and exclusion for one unselected graph.
• Tests distinguish persisted intent, active process-local intent, Core hosting obligation, and readiness.
• No new parallel mutable admission set is introduced; one current owner determines eligibility.
• Any implementation change is split from the acceptance tests and limited to a demonstrated current gap.

Provenance

• Selected-convergence and readiness scenario from RFC-64 M1 2/7: expose verified VM and SWM convergence #2012.
• Persisted/restart/scope scenarios from feat(agent): resume persisted Edge always-on sync scopes #2032, fix(agent): resume always-on SWM after restart #2036, fix(rfc64): preserve Edge periodic sync scope #2039, and fix(rfc64): resume fresh durable Edge selections #2041.
• fix(sync): make Edge on-demand synchronization point-in-time #2045 is recorded as an explicit superseded semantic choice, not an implementation source.