Implemented admin pane + user permission

docs/FUNCTIONAL_SPEC.md

@@ -236,6 +236,9 @@ A signal defined by composing one or more input signals through a chain of proce
   processing node, set parameters, Create.
 - **Node-graph editor** — a visual editor that wires one or more inputs through a chain of
   DSP blocks, for multi-input pipelines. It compiles to the same inputs + pipeline model.
+  It supports undo/redo (Ctrl+Z / Ctrl+Shift+Z) and copy/paste (Ctrl+C / Ctrl+V) of the
+  selection; paste remaps ids and preserves internal wires (the permanent output node is
+  never duplicated).
 
 **Visibility scope:** each synthetic signal is scoped as *panel* (visible only to the panel
 that created it), *user*, or *global* (shared with everyone).
@@ -303,6 +306,9 @@ managed through the REST API.
   config* makes a new instance for a set, optionally seeded from another instance. Both
   mutating nodes are audited.
 - Each graph can be enabled/disabled independently; saving reloads the engine live.
+- The editor has its own undo/redo and copy/paste (Ctrl+Z / Ctrl+Shift+Z, Ctrl+C / Ctrl+V;
+  also ↩/↪ toolbar buttons). Copy/paste is multi-select aware and preserves wires internal
+  to the selection.
 - Editing is gated by the logic-edit restriction (§2).
 
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