feat: MeshCore SAR - Flutter BLE mesh radio companion app

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/widgets/map/location_pointer.dart

@@ -0,0 +1,175 @@
+import 'package:flutter/material.dart';
+
+/// A navigation arrow pointer that indicates the user's location and direction of travel.
+///
+/// The pointer consists of:
+/// - An outer semi-transparent circle representing GPS accuracy
+/// - An inner triangular arrow pointing in the direction of travel/heading
+/// - Optional rotation based on compass or GPS heading
+class LocationPointer extends StatelessWidget {
+  /// The heading in degrees (0-360, where 0 = North, 90 = East)
+  /// If null or -1, the pointer will not rotate
+  final double? heading;
+
+  /// The primary color for the pointer
+  final Color color;
+
+  /// The size of the entire widget
+  final double size;
+
+  const LocationPointer({
+    super.key,
+    this.heading,
+    required this.color,
+    this.size = 40.0,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    // Determine if we have valid heading data
+    final hasValidHeading = heading != null && heading! >= 0;
+
+    // Calculate rotation angle (convert heading to radians)
+    final rotationAngle = hasValidHeading ? (heading! * 3.14159 / 180.0) : 0.0;
+
+    return SizedBox(
+      width: size,
+      height: size,
+      child: Stack(
+        alignment: Alignment.center,
+        children: [
+          // Outer accuracy circle (very subtle, uses theme color)
+          Container(
+            width: size * 0.6,
+            height: size * 0.6,
+            decoration: BoxDecoration(
+              color: color.withValues(alpha: 0.2),
+              shape: BoxShape.circle,
+            ),
+          ),
+          // Inner rotatable arrow pointer (much larger - 90% of size)
+          Transform.rotate(
+            angle: rotationAngle,
+            child: CustomPaint(
+              size: Size(size * 0.9, size * 0.9),
+              painter: _NavigationPointerPainter(
+                color: color,
+                hasValidHeading: hasValidHeading,
+              ),
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}
+
+/// Custom painter that draws a navigation arrow pointer
+class _NavigationPointerPainter extends CustomPainter {
+  final Color color;
+  final bool hasValidHeading;
+
+  _NavigationPointerPainter({
+    required this.color,
+    required this.hasValidHeading,
+  });
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    final center = Offset(size.width / 2, size.height / 2);
+    final width = size.width;
+    final height = size.height;
+
+    if (hasValidHeading) {
+      // Create navigation arrow with V-shaped cutout at bottom
+      final arrowPath = Path();
+
+      // Top point (sharp tip)
+      arrowPath.moveTo(center.dx, height * 0.08);
+
+      // Right side down to bottom right
+      arrowPath.lineTo(center.dx + width * 0.42, height * 0.92);
+
+      // V-cutout at bottom - right side to center
+      arrowPath.lineTo(center.dx, height * 0.70);
+
+      // V-cutout - center to left side
+      arrowPath.lineTo(center.dx - width * 0.42, height * 0.92);
+
+      // Left side back up to top
+      arrowPath.lineTo(center.dx, height * 0.08);
+
+      arrowPath.close();
+
+      // Draw shadow for depth
+      final shadowPaint = Paint()
+        ..color = Colors.black.withValues(alpha: 0.25)
+        ..style = PaintingStyle.fill
+        ..maskFilter = const MaskFilter.blur(BlurStyle.normal, 4);
+
+      canvas.save();
+      canvas.translate(2, 2);
+      canvas.drawPath(arrowPath, shadowPaint);
+      canvas.restore();
+
+      // Left side (lighter - 70% opacity of theme color)
+      final leftSidePath = Path();
+      leftSidePath.moveTo(center.dx, height * 0.08);
+      leftSidePath.lineTo(center.dx - width * 0.42, height * 0.92);
+      leftSidePath.lineTo(center.dx, height * 0.70);
+      leftSidePath.close();
+
+      final leftPaint = Paint()
+        ..color = color.withValues(alpha: 0.7)
+        ..style = PaintingStyle.fill;
+      canvas.drawPath(leftSidePath, leftPaint);
+
+      // Right side (darker - full theme color)
+      final rightSidePath = Path();
+      rightSidePath.moveTo(center.dx, height * 0.08);
+      rightSidePath.lineTo(center.dx, height * 0.70);
+      rightSidePath.lineTo(center.dx + width * 0.42, height * 0.92);
+      rightSidePath.close();
+
+      final rightPaint = Paint()
+        ..color = color
+        ..style = PaintingStyle.fill;
+      canvas.drawPath(rightSidePath, rightPaint);
+
+      // Optional: Draw white border for contrast
+      final borderPaint = Paint()
+        ..color = Colors.white
+        ..style = PaintingStyle.stroke
+        ..strokeWidth = 2.0
+        ..strokeJoin = StrokeJoin.round;
+      canvas.drawPath(arrowPath, borderPaint);
+
+    } else {
+      // No heading available - draw a circle with white border (uses theme color)
+      final circlePaint = Paint()
+        ..color = color
+        ..style = PaintingStyle.fill;
+
+      canvas.drawCircle(center, width * 0.4, circlePaint);
+
+      // White border
+      final borderPaint = Paint()
+        ..color = Colors.white
+        ..style = PaintingStyle.stroke
+        ..strokeWidth = 2.5;
+      canvas.drawCircle(center, width * 0.4, borderPaint);
+
+      // Center white dot
+      final centerDot = Paint()
+        ..color = Colors.white
+        ..style = PaintingStyle.fill;
+      canvas.drawCircle(center, width * 0.15, centerDot);
+    }
+  }
+
+  @override
+  bool shouldRepaint(_NavigationPointerPainter oldDelegate) {
+    return oldDelegate.color != color ||
+           oldDelegate.hasValidHeading != hasValidHeading;
+  }
+}