feat: Enhance user management and UI components

- Updated user API routes to include imageUrl for better user representation.
- Added @radix-ui/react-toast dependency for improved user notifications.
- Refactored dashboard and studies components to incorporate new user fields and loading states.
- Enhanced the layout and structure of the dashboard, studies, and participants pages for better user experience.
- Implemented a dialog for adding participants, improving the participant management workflow.
- Updated breadcrumb navigation to reflect the current study context more accurately.
- Cleaned up unused imports and optimized component rendering for performance.

src/app/dashboard/studies/[id]/participants/page.tsx

@@ -6,7 +6,6 @@ import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "~/com
 import { Button } from "~/components/ui/button";
 import { useToast } from "~/hooks/use-toast";
 import { Plus, Trash2 } from "lucide-react";
-import Link from "next/link";
 import { useActiveStudy } from "~/context/active-study";
 import { hasPermission } from "~/lib/permissions-client";
 import { PERMISSIONS } from "~/lib/permissions";
@@ -21,6 +20,15 @@ import {
   AlertDialogTitle,
   AlertDialogTrigger,
 } from "~/components/ui/alert-dialog";
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogFooter,
+  DialogHeader,
+  DialogTitle,
+  DialogTrigger,
+} from "~/components/ui/dialog";
 import {
   Table,
   TableBody,
@@ -30,6 +38,10 @@ import {
   TableRow,
 } from "~/components/ui/table";
 import { getApiUrl } from "~/lib/fetch-utils";
+import { Skeleton } from "~/components/ui/skeleton";
+import { Input } from "~/components/ui/input";
+import { Label } from "~/components/ui/label";
+
 interface Participant {
   id: number;
   name: string;
@@ -40,6 +52,8 @@ interface Participant {
 export default function ParticipantsList() {
   const [participants, setParticipants] = useState<Participant[]>([]);
   const [isLoading, setIsLoading] = useState(true);
+  const [isAddingParticipant, setIsAddingParticipant] = useState(false);
+  const [newParticipantName, setNewParticipantName] = useState("");
   const { id } = useParams();
   const { toast } = useToast();
   const { activeStudy } = useActiveStudy();
@@ -50,13 +64,7 @@ export default function ParticipantsList() {
 
   const fetchParticipants = useCallback(async () => {
     try {
-      const response = await fetch(getApiUrl(`/api/studies/${id}/participants`), {
-        method: "GET",
-        headers: {
-          "Content-Type": "application/json",
-        },
-      });
-
+      const response = await fetch(getApiUrl(`/api/studies/${id}/participants`));
       if (!response.ok) throw new Error("Failed to fetch participants");
       const data = await response.json();
       setParticipants(data.data || []);
@@ -70,7 +78,7 @@ export default function ParticipantsList() {
     } finally {
       setIsLoading(false);
     }
-  }, [toast, id]);
+  }, [id, toast]);
 
   useEffect(() => {
     fetchParticipants();
@@ -103,13 +111,82 @@ export default function ParticipantsList() {
     }
   };
 
+  const handleAddParticipant = async () => {
+    if (!newParticipantName.trim()) return;
+
+    setIsAddingParticipant(true);
+    try {
+      const response = await fetch(getApiUrl(`/api/studies/${id}/participants`), {
+        method: "POST",
+        headers: {
+          "Content-Type": "application/json",
+        },
+        body: JSON.stringify({ name: newParticipantName }),
+      });
+
+      if (!response.ok) throw new Error("Failed to add participant");
+
+      const data = await response.json();
+      setParticipants([...participants, data.data]);
+      setNewParticipantName("");
+      toast({
+        title: "Success",
+        description: "Participant added successfully",
+      });
+    } catch (error) {
+      console.error("Error adding participant:", error);
+      toast({
+        title: "Error",
+        description: "Failed to add participant",
+        variant: "destructive",
+      });
+    } finally {
+      setIsAddingParticipant(false);
+    }
+  };
+
   if (isLoading) {
     return (
-      <Card>
-        <CardContent className="py-8">
-          <p className="text-center text-muted-foreground">Loading participants...</p>
-        </CardContent>
-      </Card>
+      <div className="space-y-6">
+        <div className="flex items-center justify-between">
+          <div>
+            <Skeleton className="h-8 w-[200px] mb-2" />
+            <Skeleton className="h-4 w-[300px]" />
+          </div>
+          <Skeleton className="h-10 w-[140px]" />
+        </div>
+
+        <Card>
+          <CardHeader>
+            <Skeleton className="h-5 w-[150px] mb-2" />
+            <Skeleton className="h-4 w-[250px]" />
+          </CardHeader>
+          <CardContent>
+            <div className="rounded-md border">
+              <Table>
+                <TableHeader>
+                  <TableRow>
+                    <TableHead><Skeleton className="h-4 w-[40px]" /></TableHead>
+                    <TableHead><Skeleton className="h-4 w-[120px]" /></TableHead>
+                    <TableHead><Skeleton className="h-4 w-[100px]" /></TableHead>
+                    <TableHead className="w-[100px]"><Skeleton className="h-4 w-[60px]" /></TableHead>
+                  </TableRow>
+                </TableHeader>
+                <TableBody>
+                  {[1, 2, 3].map((i) => (
+                    <TableRow key={i}>
+                      <TableCell><Skeleton className="h-4 w-[30px]" /></TableCell>
+                      <TableCell><Skeleton className="h-4 w-[150px]" /></TableCell>
+                      <TableCell><Skeleton className="h-4 w-[100px]" /></TableCell>
+                      <TableCell><Skeleton className="h-8 w-8" /></TableCell>
+                    </TableRow>
+                  ))}
+                </TableBody>
+              </Table>
+            </div>
+          </CardContent>
+        </Card>
+      </div>
     );
   }
 
@@ -123,12 +200,41 @@ export default function ParticipantsList() {
           </p>
         </div>
         {canCreateParticipant && (
-          <Button asChild>
-            <Link href={`/dashboard/studies/${id}/participants/new`}>
-              <Plus className="mr-2 h-4 w-4" />
-              Add Participant
-            </Link>
-          </Button>
+          <Dialog>
+            <DialogTrigger asChild>
+              <Button>
+                <Plus className="mr-2 h-4 w-4" />
+                Add Participant
+              </Button>
+            </DialogTrigger>
+            <DialogContent>
+              <DialogHeader>
+                <DialogTitle>Add Participant</DialogTitle>
+                <DialogDescription>
+                  Add a new participant to {activeStudy?.title}
+                </DialogDescription>
+              </DialogHeader>
+              <div className="space-y-4 py-4">
+                <div className="space-y-2">
+                  <Label htmlFor="name">Participant Name</Label>
+                  <Input
+                    id="name"
+                    placeholder="Enter participant name"
+                    value={newParticipantName}
+                    onChange={(e) => setNewParticipantName(e.target.value)}
+                  />
+                </div>
+              </div>
+              <DialogFooter>
+                <Button
+                  onClick={handleAddParticipant}
+                  disabled={isAddingParticipant || !newParticipantName.trim()}
+                >
+                  {isAddingParticipant ? "Adding..." : "Add Participant"}
+                </Button>
+              </DialogFooter>
+            </DialogContent>
+          </Dialog>
         )}
       </div>
 
@@ -198,12 +304,40 @@ export default function ParticipantsList() {
               {canCreateParticipant && (
                 <>
                   .{" "}
-                  <Link
-                    href={`/dashboard/studies/${id}/participants/new`}
-                    className="font-medium text-primary hover:underline"
-                  >
-                    Add your first participant
-                  </Link>
+                  <Dialog>
+                    <DialogTrigger asChild>
+                      <Button variant="link" className="px-2 py-0">
+                        Add your first participant
+                      </Button>
+                    </DialogTrigger>
+                    <DialogContent>
+                      <DialogHeader>
+                        <DialogTitle>Add Participant</DialogTitle>
+                        <DialogDescription>
+                          Add a new participant to {activeStudy?.title}
+                        </DialogDescription>
+                      </DialogHeader>
+                      <div className="space-y-4 py-4">
+                        <div className="space-y-2">
+                          <Label htmlFor="name-empty">Participant Name</Label>
+                          <Input
+                            id="name-empty"
+                            placeholder="Enter participant name"
+                            value={newParticipantName}
+                            onChange={(e) => setNewParticipantName(e.target.value)}
+                          />
+                        </div>
+                      </div>
+                      <DialogFooter>
+                        <Button
+                          onClick={handleAddParticipant}
+                          disabled={isAddingParticipant || !newParticipantName.trim()}
+                        >
+                          {isAddingParticipant ? "Adding..." : "Add Participant"}
+                        </Button>
+                      </DialogFooter>
+                    </DialogContent>
+                  </Dialog>
                 </>
               )}
             </div>