feat(graph): add graph tab for whole-run data

Provides a static line chart plotting multi-sensor temperature values
over time when a session file is loaded.

src/pygui/ISC/HomePage.qml

@@ -238,6 +238,12 @@ Rectangle {
                             expandW: 58
                             desc: "Visualize spatial sensor readings on a 2D thin-plate spline RBF interpolated heatmap."
                         }
+                        ListElement {
+                            label: "GRAPH"
+                            icon: "Tabs/icons/bar-chart.svg"
+                            expandW: 70
+                            desc: "Whole-run multi-sensor temperature chart for the currently loaded file."
+                        }
                     }
 
                     RowLayout {
@@ -648,6 +654,10 @@ Rectangle {
                     //   so the tab never instantiates while locked. See plan §3.1.
                     active: StackLayout.index === root.selectedTabIndex
                 }
+                Loader {
+                    source: "Tabs/GraphTab.qml"
+                    active: StackLayout.index === root.selectedTabIndex
+                }
             }
         }
     }

src/pygui/ISC/Tabs/GraphTab.qml

@@ -0,0 +1,50 @@
+import QtQuick
+import QtQuick.Layouts
+import ISC
+import ISC.Wafer
+
+// ===== Graph Tab =====
+// Whole-run multi-sensor line chart (C# parity: tabGraph/chartData). Static
+// snapshot recomputed whenever a file is loaded — not live-updating during
+// a stream. See specs/plans/2026-07-10-graph-tab.md and
+// docs/adr/0003-pyqtgraph-for-multi-sensor-charts.md.
+Item {
+    id: root
+    anchors.fill: parent
+
+    function refresh() {
+        if (!streamController.loadedFile) {
+            chart.seriesData = []
+            chart.sensorNames = []
+            return
+        }
+        chart.sensorNames = streamController.graphSensorNames
+            ? streamController.graphSensorNames.split(",") : []
+        chart.seriesData = JSON.parse(streamController.graphSeriesJson || "[]")
+    }
+
+    Connections {
+        target: streamController
+        function onLoadedFileChanged() { root.refresh() }
+    }
+
+    Component.onCompleted: root.refresh()
+
+    Rectangle {
+        anchors.fill: parent
+        anchors.margins: Theme.panelPadding
+        color: Theme.cardBackground
+        border.color: Theme.cardBorder
+        border.width: 1
+        radius: Theme.radiusMd
+
+        GraphQuickItem {
+            id: chart
+            anchors.fill: parent
+            anchors.margins: 8
+            title: "Sensor Temperature Over Time"
+            xLabel: "Measurement Interval"
+            yLabel: "Temperature (°C)"
+        }
+    }
+}

src/pygui/backend/controllers/session_controller.py

@@ -11,7 +11,11 @@ from PySide6.QtCore import Property, QObject, Qt, QTimer, Signal, Slot
 from pygui.backend.cluster_average import average_clusters, group_sensors_by_radius
 from pygui.backend.data.csv_recorder import CsvRecorder
 from pygui.backend.models.frame import Frame
-from pygui.backend.models.frame_player import FramePlayer, frames_from_wafer_data
+from pygui.backend.models.frame_player import (
+    FramePlayer,
+    all_sensor_series,
+    frames_from_wafer_data,
+)
 from pygui.backend.models.frame_stats import compute_edge_center
 from pygui.backend.models.sensor_editor import SensorEditor
 from pygui.backend.models.session_model import SessionModel, SessionUpdate
@@ -207,6 +211,18 @@ class SessionController(QObject):
     @Property(str, notify=loadedFileChanged)
     def loadedFile(self) -> str: return self._loaded_file
 
+    @Property(str, notify=loadedFileChanged)
+    def graphSensorNames(self) -> str:
+        """Comma-joined sensor names for the whole-run Graph tab."""
+        names, _ = all_sensor_series(list(self._player.frames))
+        return ",".join(names)
+
+    @Property(str, notify=loadedFileChanged)
+    def graphSeriesJson(self) -> str:
+        """JSON per-sensor value series (one list per sensor) for the Graph tab."""
+        _, series = all_sensor_series(list(self._player.frames))
+        return json.dumps(series)
+
     @Property("QVariantList", notify=frameUpdated)  # type: ignore[arg-type]
     def overriddenSensors(self) -> list[int]:
         """Indices of sensors that currently have a replacement or offset."""

src/pygui/backend/models/frame_player.py

@@ -8,6 +8,19 @@ def frames_from_wafer_data(data: ZWaferData | None, records) -> list[Frame]:
     """Build Frames from parsed DataRecords (records = list[DataRecord].)"""
     return [Frame(seq=i, time=r.time, values=list(r.values)) for i, r in enumerate(records)]
 
+
+def all_sensor_series(frames: list[Frame]) -> tuple[list[str], list[list[float]]]:
+    """Per-sensor value series across every frame, for the whole-run Graph tab.
+
+    Sensor names are 1-based ("Sensor 1", ...), matching the C# original.
+    """
+    if not frames:
+        return [], []
+    n_sensors = len(frames[0].values)
+    names = [f"Sensor {i + 1}" for i in range(n_sensors)]
+    series = [[frame.values[i] for frame in frames] for i in range(n_sensors)]
+    return names, series
+
 class FramePlayer:
     def __init__(self) -> None:
         self._frames: list[Frame] =[]
@@ -22,6 +35,10 @@ class FramePlayer:
     def total(self) -> int:
         return len(self._frames)
 
+    @property
+    def frames(self) -> tuple[Frame, ...]:
+        return tuple(self._frames)
+
     @property
     def index(self) -> int:
         return self._i