Bars widget: app-driven "Track Countdown" with zero config (KC-20)

- Task long-press menu gains Track/Stop Tracking Countdown, storing the
  tracked event id + tracking date in the App Group (CountdownTracker)
  and reloading widget timelines.
- The widget reads the tracked event directly and bypasses its config:
  Mode A (one-off) = tracking date -> event date; Mode B (recurring) =
  previous occurrence -> next occurrence via the task's recurrence rule.
- WidgetTask decodes isRecurring/recurrenceLabel from the shared JSON.
- With nothing tracked, the configured modes remain the fallback.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

KisaniCal/ISSUES.md

@@ -606,3 +606,41 @@ All widgets should match the brand orange theme of the logo exactly.
 - Lock-screen ring tints → brand accent (renders in color on StandBy/home).
 
 Files: `WidgetViews.swift`, `TaskLiveActivity.swift`.
+
+---
+
+## KC-20 — "Track Countdown": zero-config bars widget driven from the app
+
+**Status:** In Progress (implemented & build-verified, pending device build)
+**Reported by:** User
+**Area:** Widgets / Tasks
+
+### Description
+The bars widget should not need manual event entry: track any KisaniCal event
+from the app and the widget displays it automatically (title, date, time left,
+progress bars).
+
+### Fix
+- **App:** new `CountdownTracker` + a "Track Countdown" / "Stop Tracking
+  Countdown" item in the shared task long-press menu. Stores
+  `kisani.widget.trackedEvent` (+ `trackedSince`) in the App Group and reloads
+  widget timelines.
+- **Widget:** the tracked event bypasses the widget configuration entirely.
+  - **Mode A** (one-off): progress = elapsed/(event − tracking date).
+  - **Mode B** (recurring birthdays/anniversaries): progress across the
+    occurrence span containing now (previous → next occurrence), derived from
+    the task's recurrence rule (`recurrenceSpan`).
+- `WidgetTask` now decodes `isRecurring`/`recurrenceLabel` from the shared JSON.
+- No tracked event → existing configuration (upcoming queue / picked / custom)
+  remains the fallback, exactly as before.
+- Bar rendering already maps progress → filled (accent) vs remaining (dimmed)
+  bars; the screenshot showing static dim bars was the pre-KC-18 build.
+
+Files: `TaskContextMenu.swift`, `WidgetData.swift`, `EventCountdownWidget.swift`.
+
+### How to test (device)
+1. Long-press any task with a due date → "Track Countdown".
+2. The bars widget switches to that event without touching its config.
+3. A yearly birthday shows Mode B: bar spans last year's → this year's date.
+4. Long-press the task again → "Stop Tracking Countdown" → widget falls back
+   to its configured mode.

KisaniCal/Views/TaskContextMenu.swift

@@ -1,4 +1,27 @@
 import SwiftUI
+import WidgetKit
+
+/// Tracks one event for the Event Countdown (Bars) widget via App Group storage.
+/// The widget reads these keys directly — no manual widget configuration needed.
+enum CountdownTracker {
+    static let idKey    = "kisani.widget.trackedEvent"
+    static let sinceKey = "kisani.widget.trackedSince"
+
+    static func isTracked(_ task: TaskItem) -> Bool {
+        UserDefaults.kisani.string(forKey: idKey) == task.id.uuidString
+    }
+
+    static func toggle(_ task: TaskItem) {
+        if isTracked(task) {
+            UserDefaults.kisani.removeObject(forKey: idKey)
+            UserDefaults.kisani.removeObject(forKey: sinceKey)
+        } else {
+            UserDefaults.kisani.set(task.id.uuidString, forKey: idKey)
+            UserDefaults.kisani.set(Date(), forKey: sinceKey)   // Mode A anchor
+        }
+        WidgetCenter.shared.reloadAllTimelines()
+    }
+}
 
 /// The unified long-press menu for a task, shared across Today, Matrix, and Calendar.
 /// Pass only the closures a given screen needs; the rest default to no-ops.
@@ -67,6 +90,11 @@ struct TaskMenuItems: View {
             Label("Add to Live Activity", systemImage: "pin.circle")
         }
 
+        Button { CountdownTracker.toggle(task) } label: {
+            Label(CountdownTracker.isTracked(task) ? "Stop Tracking Countdown" : "Track Countdown",
+                  systemImage: "timer")
+        }
+
         if let onEdit {
             Button { onEdit(task) } label: { Label("Edit", systemImage: "pencil") }
         }