Draw idle as one timeline, and let the power button answer to its owner

Claude-Session: https://claude.ai/code/session_01Ms2FbjQy31TVf3CEvQhGM8

config/dot/quickshell/services/Battery.qml

@@ -52,6 +52,21 @@ Singleton {
     property int chargeLimit: 0
     property bool chargeLimitSupported: false
 
+    // How much of its design capacity the pack still holds, as a whole
+    // percent, and how many full cycles it has been through.
+    //
+    // Both are `null` rather than 0 on the very many machines whose firmware
+    // does not report them -- every desktop, and a fair number of laptops that
+    // export cycle_count as a permanent zero. Null is the value the Power page
+    // renders as an em dash; a zero would render as a dead battery that has
+    // never been charged, which is the same class of lie as the time-to-empty
+    // estimate this service deliberately does not compute.
+    //
+    // `var` rather than `int` so that null survives: an int property would
+    // coerce it to 0 and put the lie back.
+    property var healthPercent: null
+    property var cycleCount: null
+
     readonly property bool charging: root.status === "Charging"
     readonly property bool low: root.available && !root.acOnline
         && root.percent <= Settings.batteryLowPercent
@@ -81,6 +96,20 @@ Singleton {
             thresholdFile.reload();
     }
 
+    // Wear, read through the helper rather than from sysfs directly.
+    //
+    // It is the one reading here that needs arithmetic across a variable set of
+    // files -- energy_full or charge_full, against a design capacity that may
+    // not exist, summed over however many packs the machine has -- which is
+    // exactly what the helper already does for `status`. Kept off the 20-second
+    // poll: health moves over months and cycles over days, so this runs once
+    // when the paths resolve and again whenever the Power page asks.
+    function refreshHealth(): void {
+        if (root.batteryPath === "" || healthQuery.running)
+            return;
+        healthQuery.running = true;
+    }
+
     function setChargeLimit(percent: int): void {
         if (!root.chargeLimitSupported || applyLimit.running)
             return;
@@ -118,9 +147,33 @@ Singleton {
                 }
                 if (root.batteryPath === "") {
                     root.available = false;
+                    root.healthPercent = null;
+                    root.cycleCount = null;
                     return;
                 }
                 root.refresh();
+                root.refreshHealth();
+            }
+        }
+    }
+
+    Process {
+        id: healthQuery
+        command: [root.helperPath, "status"]
+        stdout: StdioCollector {
+            onStreamFinished: {
+                try {
+                    const state = JSON.parse(this.text);
+                    // Anything that is not a number -- null, absent, a string
+                    // from a future field -- is "this machine does not say".
+                    root.healthPercent = typeof state.healthPercent === "number"
+                        ? state.healthPercent : null;
+                    root.cycleCount = typeof state.cycleCount === "number"
+                        ? state.cycleCount : null;
+                } catch (error) {
+                    root.healthPercent = null;
+                    root.cycleCount = null;
+                }
             }
         }
     }
@@ -149,6 +202,10 @@ Singleton {
         onLoadFailed: {
             root.available = false;
             root.located = false;
+            // The pack that these described is gone; keep no wear figures for
+            // a battery that is no longer there.
+            root.healthPercent = null;
+            root.cycleCount = null;
         }
     }