feat: implement full context-scoped AI chat UI in AIChatPanel

- Added AIChatPanel component with context header, user and AI message handling.
- Integrated streaming responses via IPC and error handling for chat mutations.
- Enhanced user experience with input handling and auto-scrolling features.
- Updated AppShell to derive AI chat context from the current route.
- Introduced ScrollArea component for better scrolling behavior in various dialogs.
- Added support for Tailwind typography and improved global styles.
- Updated project and task dialogs to utilize ScrollArea for better UX.

src/renderer/components/projects/ProjectSidebar.tsx

@@ -54,6 +54,7 @@ import {
   CollapsibleContent,
   CollapsibleTrigger,
 } from '@/components/ui/collapsible';
+import { ScrollArea } from '@/components/ui/scroll-area';
 import {
   Empty,
   EmptyContent,
@@ -416,7 +417,7 @@ export function ProjectSidebar({ selectedProjectId, onSelectProject }: ProjectSi
       </div>
 
       {/* Project tree */}
-      <div className="flex-1 overflow-y-auto py-1 px-1">
+      <ScrollArea className="flex-1 py-1 px-1">
         {totalProjects === 0 ? (
           <Empty>
             <EmptyHeader>
@@ -824,7 +825,7 @@ export function ProjectSidebar({ selectedProjectId, onSelectProject }: ProjectSi
           ))}
           </>
         )}
-      </div>
+      </ScrollArea>
 
       {/* Rename project dialog */}
       <Dialog