drop the manager socket, the no-op migrate branch and other ruth special cases

start_manager bound the same path register_agent binds. The migrate branch, hive-priv-sock::MANAGER_NAME and MANAGER_CONTAINER were no-ops or dead. The send allow-list docs promised a manager exemption the code never had. Tests that used ruth as the manager fixture use plain names.

docs/agent-lifecycle/config-changes.md

@@ -336,8 +336,7 @@ Differences from sub-agents:
   and `/var/lib/hyperhive/applied` → `/applied` (RO) so the root agent
   can `git fetch` deployed/failed/denied tags from any agent's
   authoritative applied repo (see "Root-agent view of applied" below).
-- `socket_server::start_manager` binds the root agent's socket,
-  pure transport with no dedicated helpers — it uses the same
+- Its socket comes from the generic per-agent registration, in the same
   per-agent runtime dir as any other agent (`/run/hyperhive/agents/ruth/`),
   not a special manager-only path.
 

docs/process/conventions.md

@@ -174,9 +174,7 @@ Each row carries enough context that the caller renders
 it directly as a bulleted list, no follow-up fetch needed.
 
 `GetLooseEnds` takes no target — it always returns the caller's own
-rows, on both the agent and manager sockets alike (the manager, `ruth`,
-is a normal agent here, just deployed automatically with different
-default permissions). `Reminder` rows always carry `owner == self`.
+rows. `Reminder` rows always carry `owner == self`.
 
 Per-variant fields: