Notice broken sessions in the bar, and offer to repair them there

Nothing tells you a session is unresumable until you try to resume it, and by
then you have usually forgotten which one it was. The widget now scans every
project on a timer and whenever the panel opens, marks its icon when something
needs fixing, and lists the affected sessions with a repair button that says
what it will drop and what it will keep before doing anything.

The scan had to get roughly eighty times cheaper first. Classifying a transcript
needs two facts - what its last message id is, and whether any Anthropic id
exists at all - and the first settles the common case alone. Reading the tail of
each file and only opening the whole thing when the tail already looks wrong
takes the sweep from ~5s to ~60ms across 59 transcripts, which is the difference
between something that can sit on a timer and something that cannot. `--all`
uses the same path, and `--json` exposes it.

The badge is a dot beside the mark rather than a recolouring of it: this widget's
job is to report which provider is active, and tinting it red to mean something
else entirely would be a lie about that.

Verified by planting a genuinely corrupted transcript, watching the scan find it
and the dot appear, then removing it and watching both clear.

omarchy/smoido.claude-mode/Panel.qml

@@ -142,6 +142,47 @@ Panel {
     }
   }
 
+  // ---- Broken transcripts
+  //
+  // Repair truncates a transcript back to its last resumable point. That is
+  // destructive enough to confirm, and reversible enough to offer: the original
+  // is backed up, the cut turns are written out as Markdown, and the same text
+  // is handed back to the session so it still knows what it did.
+  readonly property var broken: widget && widget.brokenSessions ? widget.brokenSessions : []
+  property var repairTarget: null
+
+  function askRepair(entry) {
+    root.repairTarget = entry
+    root.stage = "repair"
+  }
+
+  function doRepair() {
+    if (root.busy || !root.repairTarget) return
+    root.busy = true
+    repairProc.command = root.cli(["repair-session", String(root.repairTarget.sessionId), "--apply"])
+    repairProc.running = true
+  }
+
+  Process {
+    id: repairProc
+    running: false
+    stderr: StdioCollector {
+      waitForEnd: true
+      onStreamFinished: {
+        var msg = String(text || "").replace(/\x1b\[[0-9;]*m/g, "").trim()
+        if (msg !== "") root.lastError = msg.split("\n").pop().trim()
+      }
+    }
+    onExited: function (code) {
+      root.busy = false
+      root.repairTarget = null
+      root.stage = "list"
+      // The scan is what drives the bar's warning dot, so re-run it rather than
+      // trusting this side to have guessed the new state.
+      if (widget) widget.scanSessions()
+    }
+  }
+
   function storeServerKey() {
     remedyProc.command = root.cli(["set-key", root.serverKeyRef, "--terminal"])
     remedyProc.running = true
@@ -154,6 +195,7 @@ Panel {
     root.pendingMode = ""
     root.pendingPreset = ""
     root.serverPreset = ""
+    root.repairTarget = null
   }
 
   function switchTo(mode, presetName) {
@@ -967,6 +1009,127 @@ Panel {
         }
       }
 
+
+      // ---- Sessions that a switch cut short. Shown in the list, because the
+      // point is to be noticed without going looking.
+      Column {
+        width: parent.width
+        visible: root.stage === "list" && root.broken.length > 0
+        spacing: Style.space(4)
+
+        PanelSeparator { width: parent.width }
+
+        Text {
+          width: parent.width
+          text: root.broken.length === 1
+            ? "1 session cannot be resumed"
+            : root.broken.length + " sessions cannot be resumed"
+          color: root.urgentColor
+          wrapMode: Text.WordWrap
+          font.family: root.bar ? root.bar.fontFamily : Style.font.family
+          font.pixelSize: Style.space(11)
+          font.bold: true
+        }
+
+        Repeater {
+          model: root.stage === "list" ? root.broken : []
+
+          Item {
+            required property var modelData
+            width: column.width
+            height: Style.space(26)
+
+            Column {
+              anchors.left: parent.left
+              anchors.right: repairBtn.left
+              anchors.rightMargin: Style.space(6)
+              anchors.verticalCenter: parent.verticalCenter
+              spacing: 0
+
+              Text {
+                width: parent.width
+                text: String(parent.parent.modelData.sessionId).substring(0, 8)
+                    + "  ·  " + String(parent.parent.modelData.project).replace(/^-/, "").replace(/-/g, "/")
+                color: Color.popups.text
+                elide: Text.ElideMiddle
+                font.family: root.bar ? root.bar.fontFamily : Style.font.family
+                font.pixelSize: Style.space(10)
+              }
+
+              Text {
+                width: parent.width
+                text: parent.parent.modelData.dropLines + " turn lines after the last good message"
+                color: Color.muted
+                elide: Text.ElideRight
+                font.family: root.bar ? root.bar.fontFamily : Style.font.family
+                font.pixelSize: Style.space(9)
+              }
+            }
+
+            PillButton {
+              id: repairBtn
+              anchors.right: parent.right
+              anchors.verticalCenter: parent.verticalCenter
+              label: "Repair"
+              onTriggered: root.askRepair(parent.modelData)
+            }
+          }
+        }
+      }
+
+      // ---- Confirming one repair.
+      Column {
+        width: parent.width
+        visible: root.stage === "repair" && root.repairTarget !== null
+        spacing: Style.space(7)
+
+        Text {
+          width: parent.width
+          text: "Repair " + (root.repairTarget ? String(root.repairTarget.sessionId).substring(0, 8) : "")
+          color: Color.popups.text
+          font.family: root.bar ? root.bar.fontFamily : Style.font.family
+          font.pixelSize: Style.space(13)
+          font.bold: true
+        }
+
+        Text {
+          width: parent.width
+          text: {
+            if (!root.repairTarget) return ""
+            var p = (root.repairTarget.providers || []).join(", ")
+            return "This session took " + (p !== "" ? p + "'s" : "another provider's")
+                 + " output while the mode was switched under it, and Anthropic will not "
+                 + "resume it. Rolling it back to its last good message drops "
+                 + root.repairTarget.dropLines + " lines."
+          }
+          color: Color.muted
+          wrapMode: Text.WordWrap
+          lineHeight: 1.2
+          font.family: root.bar ? root.bar.fontFamily : Style.font.family
+          font.pixelSize: Style.space(10)
+        }
+
+        Text {
+          width: parent.width
+          text: "The original is backed up, the dropped turns are saved as Markdown, "
+              + "and handed back to the session so it still knows what it did."
+          color: Color.muted
+          opacity: 0.85
+          wrapMode: Text.WordWrap
+          lineHeight: 1.2
+          font.family: root.bar ? root.bar.fontFamily : Style.font.family
+          font.pixelSize: Style.space(10)
+        }
+
+        Flow {
+          width: parent.width
+          spacing: Style.space(7)
+
+          PillButton { label: "Repair it"; primary: true; onTriggered: root.doRepair() }
+          PillButton { label: "Cancel";    onTriggered: root.resetFlow() }
+        }
+      }
+
       PanelSeparator { width: parent.width; visible: root.modelRows.length > 0 && root.stage === "list" }
 
       Column {