refactor: Centralize UI component creation

This commit centralizes the creation of common UI components into
`ui/components.py`, promoting code reuse and consistency.

- Created functions for creating labels, entries, buttons, combos,
  and text boxes.
- Replaced direct widget creation in MainWindow with calls to
  these functions.

ui/components.py

@@ -0,0 +1,22 @@
+# timelogix/ui/components.py
+import customtkinter as ctk
+
+
+def create_label(parent, text, font_family, font_size):
+    return ctk.CTkLabel(parent, text=text, font=(font_family, font_size))
+
+
+def create_entry(parent, width):
+    return ctk.CTkEntry(parent, width=width)
+
+
+def create_button(parent, text, command):
+    return ctk.CTkButton(parent, text=text, command=command, corner_radius=8)
+
+
+def create_combo(parent, values, width):
+    return ctk.CTkComboBox(parent, values=values, width=width)
+
+
+def create_text_box(parent, width, height, font):
+    return ctk.CTkTextbox(parent, width=width, height=height, font=font)