clippy: shed dead archivist handle, drop needless borrow

the mandate that 'own' promised to open is already read via
cadence_root; the & in front of format! trips
needless_borrows_for_generic_args on 1.94

src/core/archivist/mod.rs

@@ -234,10 +234,6 @@ impl ArchivistEngine {
         let started_at = Utc::now();
         let primary_id = crate::core::cadence::primary_of(agent_id);
         let repo = self.agents.memory_repo(primary_id);
-        // Her own tree, for her own mandate and pages.
-        let own = self
-            .agents
-            .cadence_memory_repo(primary_id, Cadence::Archivist);
         // The primary's tree, opened under the archivist's name: a memoir
         // landing in `system/synthesized/` stays legible as a later reading
         // rather than something she wrote at the time.

src/core/reflection/mod.rs

@@ -245,7 +245,7 @@ impl ReflectionEngine {
             } else if remaining <= REFLECTION_BUDGET_WARNING_AT {
                 request_messages.push(Message::text(
                     "system",
-                    &format!(
+                    format!(
                         "{remaining} tool rounds remain, then a final round for the \
                          report. Finish the writes that matter and let the rest go."
                     ),