enable clippy::must_use_candidate, add #[must_use] to the 3 flagged fns

Cargo.toml

@@ -44,7 +44,6 @@ pedantic = { level = "deny", priority = -1 }
 missing_errors_doc = "allow"
 missing_panics_doc = "allow"
 module_name_repetitions = "allow"
-must_use_candidate = "allow"
 
 [workspace.lints.rustdoc]
 # Doc-link rot has no other discoverer: clippy does not read intra-doc

hive-host-sock/src/lib.rs

@@ -487,6 +487,7 @@ pub struct LifecycleScope {
 impl LifecycleScope {
     /// True when nothing is explicitly selected — interpreted as "all
     /// classes" (the bare `hivectl stop` / `start` with no scope flags).
+    #[must_use]
     pub fn is_everything(&self) -> bool {
         !(self.agents || self.ci || self.forge || self.gateway || self.matrix)
             && self.agent_names.is_empty()

hive-matrix-mcp/src/handlers.rs

@@ -628,6 +628,7 @@ pub async fn list_room_members(client: &Client, room_ref: &str) -> DaemonRespons
     DaemonResponse::ok(&list)
 }
 
+#[must_use]
 pub fn list_invites(client: &Client) -> DaemonResponse {
     let invites: Vec<InviteInfo> = client
         .invited_rooms()

hive-priv-sock/src/lib.rs

@@ -61,6 +61,7 @@ pub enum InfraAction {
 
 impl InfraAction {
     /// The `systemctl` subcommand this action maps to.
+    #[must_use]
     pub fn systemctl_verb(self) -> &'static str {
         match self {
             InfraAction::Start => "start",