implement chat messaging with event proposals

- Add functional chat with server communication and test responses
- Add ProposedEventCard component for confirm/reject actions
- Move Constants (Day, Month) from client to shared package
- Add dateHelpers utility for weekday calculations
- Extend Themes.tsx with button and text colors
- Update CLAUDE.md with current implementation status
- Add *.tsbuildinfo to .gitignore

apps/client/src/Themes.tsx

@@ -5,6 +5,12 @@ type Theme = {
   messageBorderBg: string,
   placeholderBg: string,
   calenderBg: string,
+  confirmButton: string,
+  rejectButton: string,
+  disabledButton: string,
+  buttonText: string,
+  textSecondary: string,
+  textMuted: string,
 }
 
 const defaultLight: Theme = {
@@ -14,6 +20,12 @@ const defaultLight: Theme = {
   messageBorderBg: "#FFFFFF",
   placeholderBg: "#D9D9D9",
   calenderBg: "#FBD5B2",
+  confirmButton: "#22c55e",
+  rejectButton: "#ef4444",
+  disabledButton: "#ccc",
+  buttonText: "#fff",
+  textSecondary: "#666",
+  textMuted: "#888",
 }
 
 let currentTheme: Theme = defaultLight;