docs(#1014): update stale root→ruth references in conventions, approvals, agent-hierarchy

docs/conventions.md

@@ -7,7 +7,7 @@ exist because something already went wrong without them.
 
 - Containers are length-bounded by `nixos-container` (≤ 11 chars).
 - Sub-agents are `h-<name>` with `<name>` ≤ 9 chars.
-- The manager is `root` (no `h-` prefix, fixed name).
+- The manager is `ruth` (fixed name).
 - `MAX_AGENT_NAME` in `lifecycle.rs` enforces the cap.
 - Per-agent web UI port = `WEB_PORT_BASE + FNV1a(name) % WEB_PORT_RANGE`
   (8100..8999) for every agent including the manager; dashboard
@@ -331,7 +331,7 @@ that allows the underlying resource access.
 
 **Config storage** — per-agent capabilities live in
 `/var/lib/hyperhive/meta/capabilities.json` alongside `tool-groups.json`.
-Format: `{ "atlas": ["read_host_journal"], "root": ["manage_root_agent"] }`.
+Format: `{ "atlas": ["read_host_journal"], "ruth": ["manage_root_agent"] }`.
 An absent entry means "no extra capabilities". `render_flake` in `meta.rs`
 reads this file and injects `HIVE_CAPABILITIES` (comma-separated
 `snake_case` names) into each agent's systemd service env; absent entries emit