Merge branch 'main' into worktree-agent-aecd35c3421bad4ae

# Conflicts:
#	crates/ui-egui/src/render.rs

crates/engine/src/cmd/query.rs

@@ -166,6 +166,18 @@ pub fn specs() -> Vec<CommandSpec> {
             }
             Ok(json!({"enabled": lightcraft_gpu::enabled(), "available": lightcraft_gpu::available(), "adapter": lightcraft_gpu::adapter_name()}))
         }),
+        cmd!(query "library.memory", "Memory Usage", [], None, "{} — bytes held by each cache (decoded sources, rendered previews, GPU buffers; heap when instrumented)", always, |s, _| {
+            Ok(serde_json::to_value(s.memory_report()).unwrap_or_default())
+        }),
+        cmd!(query "app.memoryBudget", "Memory Budget", [], None, "{mb?: number} — set the memory budget shared by the caches (default: a quarter of RAM, at most 1536 MB); returns the report", always, |s, p| {
+            if let Some(mb) = p.get("mb").and_then(Value::as_f64) {
+                if !(64.0..=1_048_576.0).contains(&mb) {
+                    return Err(bad("app.memoryBudget", "mb must be 64..1048576"));
+                }
+                s.set_memory_budget((mb * 1048576.0) as usize);
+            }
+            Ok(serde_json::to_value(s.memory_report()).unwrap_or_default())
+        }),
         cmd!(query "journal.list", "Command Journal", [], None, "{limit?}", always, |s, p| {
             let lim = p.get("limit").and_then(Value::as_u64).unwrap_or(100) as usize;
             let start = s.journal.len().saturating_sub(lim);