feat: add table_calendar package and CalendarEvent model with tests

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

pubspec.lock

@@ -408,6 +408,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "4.8.0"
+  intl:
+    dependency: transitive
+    description:
+      name: intl
+      sha256: "3df61194eb431efc39c4ceba583b95633a403f46c9fd341e550ce0bfa50e9aa5"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.20.2"
   io:
     dependency: transitive
     description:
@@ -952,6 +960,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "3.0.0"
+  simple_gesture_detector:
+    dependency: transitive
+    description:
+      name: simple_gesture_detector
+      sha256: ba2cd5af24ff20a0b8d609cec3f40e5b0744d2a71804a2616ae086b9c19d19a3
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.2.1"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -1021,6 +1037,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "3.4.0"
+  table_calendar:
+    dependency: "direct main"
+    description:
+      name: table_calendar
+      sha256: "0c0c6219878b363a2d5f40c7afb159d845f253d061dc3c822aa0d5fe0f721982"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.2.0"
   term_glyph:
     dependency: transitive
     description: