Move time window to per-plot spinbox in control bar

Replaces the single global toolbar spinbox with one QSpinBox per plot,
placed between the '+' button and the trace chips. Each plot has an
independent 1–24 h window; values are persisted in plot_settings.json
under 'time_windows'.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

gui_client.py

@@ -349,25 +349,10 @@ class PlotTab(QWidget):
         main_layout.setContentsMargins(4, 4, 4, 4)
         main_layout.setSpacing(4)
 
-        # ── toolbar ───────────────────────────────────────────────────────────
-        tb = QWidget()
-        tb.setMaximumHeight(32)
-        tb_row = QHBoxLayout(tb)
-        tb_row.setContentsMargins(0, 0, 0, 0)
-        tb_row.setSpacing(6)
-        tb_row.addWidget(QLabel("Time window:"))
-        self._tw_spin = QSpinBox()
-        self._tw_spin.setRange(1, 24)
-        self._tw_spin.setSuffix(" h")
-        self._tw_spin.setFixedWidth(72)
-        self._tw_spin.valueChanged.connect(self._on_time_window_changed)
-        tb_row.addWidget(self._tw_spin)
-        tb_row.addStretch()
-        main_layout.addWidget(tb)
-
         # ── data ──────────────────────────────────────────────────────────────
+        self._tw_spins:     list[QSpinBox]   = []
         self._traces:       list[list[str]]  = [[] for _ in range(self.NUM_PLOTS)]
-        self._saved_traces: list[list[str]] = self._load_settings()
+        self._saved_traces, _saved_tw = self._load_settings()
         self._series: dict[str, deque] = {}
         self._units:  dict[str, str]   = {}
 
@@ -411,7 +396,16 @@ class PlotTab(QWidget):
             add_btn.clicked.connect(lambda checked, idx=i: self._add_trace(idx))
             ctrl_row.addWidget(add_btn)
 
-            ctrl_row.addSpacing(8)
+            tw_spin = QSpinBox()
+            tw_spin.setRange(1, 24)
+            tw_spin.setSuffix(" h")
+            tw_spin.setFixedWidth(60)
+            tw_spin.setValue(_saved_tw[i])
+            tw_spin.valueChanged.connect(lambda _, idx=i: self._on_time_window_changed(idx))
+            self._tw_spins.append(tw_spin)
+            ctrl_row.addWidget(tw_spin)
+
+            ctrl_row.addSpacing(4)
             chip_bar = QHBoxLayout()
             chip_bar.setSpacing(4)
             chip_bar.setContentsMargins(0, 0, 0, 0)
@@ -559,36 +553,36 @@ class PlotTab(QWidget):
             _SETTINGS_PATH.parent.mkdir(parents=True, exist_ok=True)
             _SETTINGS_PATH.write_text(json.dumps({
                 "traces":       [list(t) for t in self._traces],
-                "time_window": self._tw_spin.value(),
+                "time_windows": [sp.value() for sp in self._tw_spins],
             }, indent=2))
         except OSError:
             pass
 
-    def _load_settings(self) -> list[list[str]]:
+    def _load_settings(self) -> tuple[list[list[str]], list[int]]:
         try:
             data  = json.loads(_SETTINGS_PATH.read_text())
             saved = data.get("traces", [])
             while len(saved) < self.NUM_PLOTS:
                 saved.append([])
-            tw = int(data.get("time_window", 1))
-            self._tw_spin.blockSignals(True)
-            self._tw_spin.setValue(max(1, min(24, tw)))
-            self._tw_spin.blockSignals(False)
-            return [list(t) for t in saved[: self.NUM_PLOTS]]
-        except (OSError, json.JSONDecodeError, KeyError, AttributeError):
-            return [[] for _ in range(self.NUM_PLOTS)]
+            tws = data.get("time_windows", [])
+            while len(tws) < self.NUM_PLOTS:
+                tws.append(1)
+            tws = [max(1, min(24, int(v))) for v in tws[: self.NUM_PLOTS]]
+            return [list(t) for t in saved[: self.NUM_PLOTS]], tws
+        except (OSError, json.JSONDecodeError, KeyError):
+            return [[] for _ in range(self.NUM_PLOTS)], [1] * self.NUM_PLOTS
 
     # ── drawing ───────────────────────────────────────────────────────────────
 
-    def _on_time_window_changed(self):
+    def _on_time_window_changed(self, plot_idx: int):
         self._save_settings()
         self._redraw()
 
     def _redraw(self):
         now = time.time()
-        cutoff = now - self._tw_spin.value() * 3600
 
         for i, pw in enumerate(self._plot_widgets):
+            cutoff = now - self._tw_spins[i].value() * 3600
             pi = pw.getPlotItem()
             pi.clear()
             pi.addItem(self._vlines[i], ignoreBounds=True)