Added signal graphing

BEdit/AGENTS.md

@@ -139,6 +139,16 @@ Keep the root of `src/bedit` minimal. New UI modules should go into the relevant
 - After a successful OpenModelica run, `<model>_res.csv` is parsed on the worker
   before temporary-directory cleanup. `SimulationResults.data` stores every CSV
   column as a numeric array, including `time`, for later plotting and persistence.
+- The simulation window's dockable Signals tree derives hierarchy from dot-separated
+  result-column names and bracketed array indices (`a[1]` becomes `a → 1`). Leaf
+  items retain the exact full column name in `UserRole`; plotting code should
+  consume `SimulationWindow.selected_signal_names()`.
+- Simulation graph tabs persist as `SimulationResults.graphs`; every graph has a
+  stable ID, editable title, and its own `traces` list. Runtime graph widgets belong
+  in `GraphWorkspacePage.plot_layout`, not in the serialized core model. The
+  Signals tree checkboxes edit the active graph's traces, and each page embeds a
+  Matplotlib QtAgg canvas. Each graph persists its own `x_axis` signal (default
+  `time`), selectable from the Signals tree context menu.
 - The optional OpenModelica executable is persisted as
   `simulation/openModelicaPath`. The GUI passes it into `Simulation`; core must
   not read `QSettings`. An empty path uses OMPython/PATH discovery, while an