Integration and add heat map demo

- Implemented OpenStreetMap using WebView with Leaflet.js
- Added OpenStreetMapView component with interactive map functionality
- Created heat map visualization with color-coded intensity
- Added 30 dummy location points around San Francisco Bay Area
- Implemented location tracking with real-time pin placement
- Added comprehensive UI with two-row button layout
- Features: Start/Stop tracking, Center map, Demo heat map, Clear demo, Reset map
- Added location count display and confirmation dialogs
- Updated project structure and documentation
- All functionality tested and working on Android emulator

LocationTrackerApp/Data/LocationDbContext.cs

@@ -0,0 +1,143 @@
+using Microsoft.EntityFrameworkCore;
+using LocationTrackerApp.Models;
+
+namespace LocationTrackerApp.Data;
+
+/// <summary>
+/// Entity Framework DbContext for managing location data in SQLite database
+/// </summary>
+public class LocationDbContext : DbContext
+{
+    /// <summary>
+    /// Database path for SQLite storage
+    /// </summary>
+    public string DatabasePath { get; }
+
+    /// <summary>
+    /// DbSet for LocationData entities
+    /// </summary>
+    public DbSet<LocationData> LocationData { get; set; } = null!;
+
+    /// <summary>
+    /// Initializes a new instance of LocationDbContext
+    /// </summary>
+    /// <param name="databasePath">Path to the SQLite database file</param>
+    public LocationDbContext(string databasePath)
+    {
+        DatabasePath = databasePath;
+    }
+
+    /// <summary>
+    /// Configures the database connection and options
+    /// </summary>
+    /// <param name="optionsBuilder">Options builder for configuring the database</param>
+    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
+    {
+        optionsBuilder.UseSqlite($"Data Source={DatabasePath}");
+        
+        // Enable sensitive data logging for development (remove in production)
+        #if DEBUG
+        optionsBuilder.EnableSensitiveDataLogging();
+        #endif
+    }
+
+    /// <summary>
+    /// Configures entity relationships and constraints
+    /// </summary>
+    /// <param name="modelBuilder">Model builder for configuring entities</param>
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        base.OnModelCreating(modelBuilder);
+
+        // Configure LocationData entity
+        modelBuilder.Entity<LocationData>(entity =>
+        {
+            // Set primary key
+            entity.HasKey(e => e.Id);
+
+            // Configure indexes for better query performance
+            entity.HasIndex(e => e.Timestamp)
+                  .HasDatabaseName("IX_LocationData_Timestamp");
+
+            entity.HasIndex(e => e.SessionId)
+                  .HasDatabaseName("IX_LocationData_SessionId");
+
+            entity.HasIndex(e => new { e.Latitude, e.Longitude })
+                  .HasDatabaseName("IX_LocationData_Coordinates");
+
+            // Configure column types and constraints
+            entity.Property(e => e.Latitude)
+                  .HasColumnType("REAL")
+                  .IsRequired();
+
+            entity.Property(e => e.Longitude)
+                  .HasColumnType("REAL")
+                  .IsRequired();
+
+            entity.Property(e => e.Accuracy)
+                  .HasColumnType("REAL")
+                  .HasDefaultValue(0.0);
+
+            entity.Property(e => e.Altitude)
+                  .HasColumnType("REAL");
+
+            entity.Property(e => e.Speed)
+                  .HasColumnType("REAL");
+
+            entity.Property(e => e.Timestamp)
+                  .HasColumnType("TEXT")
+                  .IsRequired();
+
+            entity.Property(e => e.SessionId)
+                  .HasColumnType("TEXT")
+                  .HasMaxLength(100);
+
+            entity.Property(e => e.Notes)
+                  .HasColumnType("TEXT")
+                  .HasMaxLength(500);
+        });
+    }
+
+    /// <summary>
+    /// Ensures the database is created and up to date
+    /// </summary>
+    public async Task EnsureDatabaseCreatedAsync()
+    {
+        await Database.EnsureCreatedAsync();
+    }
+
+    /// <summary>
+    /// Clears all location data from the database
+    /// </summary>
+    public async Task ClearAllLocationDataAsync()
+    {
+        await Database.ExecuteSqlRawAsync("DELETE FROM LocationData");
+    }
+
+    /// <summary>
+    /// Gets location data within a specified time range
+    /// </summary>
+    /// <param name="startTime">Start time for the query</param>
+    /// <param name="endTime">End time for the query</param>
+    /// <returns>List of location data within the time range</returns>
+    public async Task<List<LocationData>> GetLocationDataInTimeRangeAsync(DateTime startTime, DateTime endTime)
+    {
+        return await LocationData
+            .Where(l => l.Timestamp >= startTime && l.Timestamp <= endTime)
+            .OrderBy(l => l.Timestamp)
+            .ToListAsync();
+    }
+
+    /// <summary>
+    /// Gets location data for a specific session
+    /// </summary>
+    /// <param name="sessionId">Session identifier</param>
+    /// <returns>List of location data for the session</returns>
+    public async Task<List<LocationData>> GetLocationDataBySessionAsync(string sessionId)
+    {
+        return await LocationData
+            .Where(l => l.SessionId == sessionId)
+            .OrderBy(l => l.Timestamp)
+            .ToListAsync();
+    }
+}