hivectl: add hive-wide start/stop verbs

`hivectl stop` brings the whole hive down in one operator action — all
sub-agents plus the ci/forge/gateway/matrix infra containers — and
`hivectl start` brings it back up. Scope flags (--agents, --agent <name>,
--ci, --forge, --gateway, --matrix) narrow the set; a bare invocation
targets everything. hive-c0re never stops itself.

- hive-sh4re: HostRequest::{Stop,Start} + LifecycleScope wire type;
  priv_proto InfraAction + ControlInfraContainer + the
  CONTROLLABLE_INFRA_CONTAINERS allowlist (adds hive-matrix, excludes
  hive-c0re).
- hive-priv: control_infra_container handler (systemctl <verb>
  container@<name>, allowlist-validated root-side).
- hive-c0re: handle_stop / handle_start fan out agents via lifecycle and
  infra via hive-priv; per-target failures are aggregated. Infra
  systemctl routes through hive-priv (the privsep boundary).
- The --graceful flag is threaded through Stop now; the per-agent quiesce
  itself lands with the graceful-agent-stop work.

hive-sh4re/src/lib.rs

@@ -58,6 +58,68 @@ pub enum HostRequest {
         child: String,
         new_parent: Option<String>,
     },
+    /// Stop managed containers hive-wide in one operator action
+    /// (`hivectl stop`): agents plus the selected infra containers. `scope`
+    /// selects which classes; an all-false scope means **everything** (the
+    /// bare `hivectl stop`). `graceful` runs the per-agent quiesce (graceful
+    /// agent stop, issue tracker `graceful agent stop`) instead of a hard
+    /// stop. Agents stop via the lifecycle path; infra containers via the
+    /// host `container@<name>` units.
+    Stop {
+        #[serde(default)]
+        scope: LifecycleScope,
+        #[serde(default)]
+        graceful: bool,
+    },
+    /// Start managed containers hive-wide — the inverse of `Stop`
+    /// (`hivectl start`). Same `scope` semantics (all-false = everything);
+    /// no graceful flag (start is unconditional).
+    Start {
+        #[serde(default)]
+        scope: LifecycleScope,
+    },
+}
+
+/// Selects which container classes a hive-wide [`HostRequest::Stop`] /
+/// [`HostRequest::Start`] touches. An all-false scope means **everything**
+/// (the bare `hivectl stop` / `start`); set individual fields to restrict
+/// (e.g. only `agents` → just the sub-agent containers). `agents` covers
+/// every managed sub-agent container; the rest are the named infra
+/// containers (`hive-ci`, `hive-forge`, `hive-gateway`, `hive-matrix`).
+//
+// A flat bag of independent flag toggles — one bool per selectable
+// container class — is exactly the right shape here: each maps 1:1 to a
+// `hivectl` `--ci` / `--forge` / `--gateway` / `--matrix` flag, and they're
+// orthogonal (any subset is valid), so a state machine or two-variant enums
+// would only obscure the mapping. Hence the `struct_excessive_bools` allow.
+#[allow(clippy::struct_excessive_bools)]
+#[derive(Debug, Clone, Default, Serialize, Deserialize)]
+pub struct LifecycleScope {
+    /// All sub-agent containers (`--agents`).
+    #[serde(default)]
+    pub agents: bool,
+    /// Specific sub-agents by logical name (`--agent <name>`, repeatable).
+    /// Additive with the rest of the scope; redundant when `agents` is set
+    /// (which already covers every sub-agent).
+    #[serde(default)]
+    pub agent_names: Vec<String>,
+    #[serde(default)]
+    pub ci: bool,
+    #[serde(default)]
+    pub forge: bool,
+    #[serde(default)]
+    pub gateway: bool,
+    #[serde(default)]
+    pub matrix: bool,
+}
+
+impl LifecycleScope {
+    /// True when nothing is explicitly selected — interpreted as "all
+    /// classes" (the bare `hivectl stop` / `start` with no scope flags).
+    pub fn is_everything(&self) -> bool {
+        !(self.agents || self.ci || self.forge || self.gateway || self.matrix)
+            && self.agent_names.is_empty()
+    }
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]