Detailed Description
Composes the shared EntitySelectionList primitive introduced by §IM-3 Phase 4. Mirrors the UX of NodeSelectionActivity so the two picker screens look and feel the same: identicon + display name + subtitle + lastUsed pill, always-on Create action, "Device owner" emphasis on the row whose SID matches the registry's device owner.
Row resolution path (in priority order): 1. SentientEntry matched by storePath → real SID, displayName, shadow/secured tag, identicon from the real public-key hash. This is the §HT-6 recovery path that correlates a legacy "System" hive (renamed to "SID-legacy-<uuid8>") with its real sentient by on-disk path. 2. SentientEntry matched by raw SID — modern post-§SP-2 hives. 3. Fallback — show a "Legacy hive · <uuid8>" row with an identicon derived from the hive UUID so the two legacy rows are at least visually distinct even when no SentientEntry can be correlated.
The activity pops with ["selected", sentientId] (real SID hex, no "SID-" prefix) or ["create-new"]. The startup state machine consumes the former via proceedWithSentient.
Spec: content/doc/internal/specs/startup-identity-unification/select-activities.md