Segment membership Edge dashboard hooks

[khvn26]

Scope

• EdgeIdentity create / update / delete service-layer entry points enqueue the existing process_identity_* / process_traits_changed tasks the index already consumes.

Acceptance criteria

• Creating an EdgeIdentity from the dashboard creates a core Identity row and flips bits in "identifier" / "identity_key" atoms for the env.
• Updating an EdgeIdentity's traits flips bits in "trait" atoms whose property changed.
• Deleting an EdgeIdentity clears all bits at that identity's PK.