Widgets: add shared WidgetTheme + BarGrid (foundation)

Groundwork for the slate-background / brand-orange widget re-theme and the
new bar-style event countdown:
- WidgetTheme (dark slate background, brand orange accent, text tones).
- BarGrid: vertical-bar (comb) progress view.

Re-theming the existing widgets and adding the bars widget follows.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

KisaniCalWidgets/WidgetViews.swift

@@ -1,6 +1,41 @@
 import SwiftUI
 import WidgetKit
 
+// MARK: - Shared widget theme (slate background + brand orange)
+
+enum WidgetTheme {
+    static let background = Color(red: 0.224, green: 0.255, blue: 0.310) // dark slate
+    static let accent     = Color(red: 0.93,  green: 0.42,  blue: 0.20)  // brand orange
+    static let text       = Color.white
+    static let textDim    = Color.white.opacity(0.55)
+    static let textFaint  = Color.white.opacity(0.4)
+}
+
+// MARK: - Vertical-bar progress (comb / equalizer style)
+
+struct BarGrid: View {
+    let progress: Double          // 0…1
+    let color: Color
+    var count: Int = 64
+    var gap: CGFloat = 3
+
+    var body: some View {
+        GeometryReader { geo in
+            let totalGap = gap * CGFloat(count - 1)
+            let barW = max(1.5, (geo.size.width - totalGap) / CGFloat(count))
+            let filled = Int((progress * Double(count)).rounded())
+            HStack(spacing: gap) {
+                ForEach(0..<count, id: \.self) { i in
+                    RoundedRectangle(cornerRadius: barW / 2)
+                        .fill(i < filled ? color : color.opacity(0.22))
+                        .frame(width: barW)
+                }
+            }
+            .frame(height: geo.size.height, alignment: .center)
+        }
+    }
+}
+
 // MARK: - Dot-grid progress (day / week / month / year)
 
 enum TimePeriod { case day, week, month, year }