Refactor App layout and enhance UI components for better usability

- Changed the default active tab in the App component from 'profiles' to 'main'.
- Improved the layout of the main content area to better accommodate different views, including profiles, generation forms, and history.
- Updated Sidebar component to reflect the new tab structure with a 'main' tab.
- Enhanced the GenerationForm to utilize the selected profile from the UI store, improving user feedback when no profile is selected.
- Added a new CircleButton component for better icon button interactions.
- Adjusted styles in various components for improved responsiveness and visual consistency.

app/src/stores/uiStore.ts

@@ -14,6 +14,10 @@ interface UIStore {
   generationDialogOpen: boolean;
   setGenerationDialogOpen: (open: boolean) => void;
 
+  // Selected profile for generation
+  selectedProfileId: string | null;
+  setSelectedProfileId: (id: string | null) => void;
+
   // Theme
   theme: 'light' | 'dark';
   setTheme: (theme: 'light' | 'dark') => void;
@@ -31,6 +35,9 @@ export const useUIStore = create<UIStore>((set) => ({
   generationDialogOpen: false,
   setGenerationDialogOpen: (open) => set({ generationDialogOpen: open }),
 
+  selectedProfileId: null,
+  setSelectedProfileId: (id) => set({ selectedProfileId: id }),
+
   theme: 'light',
   setTheme: (theme) => {
     set({ theme });