Refactors calendar architecture for month view

Prepares the calendar component for month view implementation
by introducing a strategy pattern for view management,
splitting configuration settings, and consolidating events
into a core set. It also removes dead code and enforces type safety,
improving overall code quality and maintainability.

Addresses critical issues identified in the code review,
laying the groundwork for efficient feature addition.

.claude/settings.local.json

@@ -6,7 +6,8 @@
       "Bash(powershell:*)",
       "Bash(rg:*)",
       "Bash(find:*)",
-      "Bash(mv:*)"
+      "Bash(mv:*)",
+      "Bash(rm:*)"
     ],
     "deny": []
   }