Add EventOccurrenceParserService and update service registrations

Registered the new EventOccurrenceParserService in Program.cs to handle event occurrence parsing. Updated the _Imports.razor file to reflect the renaming of the EventCalendar component to Calendar. Removed the obsolete EventCalendar component to streamline the codebase.

Core/Services/IEventOccurrenceParserService.cs

@@ -0,0 +1,19 @@
+using Core.Entities;
+using Core.Models;
+
+namespace Core.Services;
+
+/// <summary>
+/// Service interface for parsing event occurrence text data.
+/// </summary>
+public interface IEventOccurrenceParserService
+{
+    /// <summary>
+    /// Parses event occurrence text data and returns parse results with occurrences, errors, and warnings.
+    /// </summary>
+    /// <param name="text">The text content to parse (typically multi-line text from paste/import)</param>
+    /// <param name="events">Collection of EventDefinitions to match against during parsing</param>
+    /// <returns>ParseResult containing parsed occurrences, errors, and warnings</returns>
+    EventOccurrenceParseResult ParseFromText(string text, ICollection<EventDefinition> events);
+}
+