hive reads the forge for nix as its own account, not core

hive-c0re copies the hive's store read token to /run/hyperhive/forge-hive-token
for nix's git credential helper, and no longer mints, reads or falls back to
the core admin token. drops the core user sweep, avatar upload, webhook
cleanup and hive-priv's RunForgeAdmin.

hive-c0re/src/job_queue/model.rs

@@ -96,8 +96,8 @@ pub enum NodeKind {
     /// Write the agent's durable power intent (`wanted = Up` when `up`,
     /// else `Offline`) as the head node of a power-op DAG.
     SetWanted { agent: String, up: bool },
-    /// One-shot boot-time forge user/token sweep for every existing
-    /// container (`forge::ensure_all`). Agentless.
+    /// One-shot boot-time publish of the hive's forge read token for nix
+    /// (`forge::ensure_all`). Agentless.
     ForgeSweep,
     /// Matrix user/space sweep (`matrix::ensure_all`): at boot and every 30
     /// minutes. Agentless.