feat: add workspace management features including member invitations and role updates

- Implemented API endpoints for managing workspace members (GET, POST, PATCH, DELETE).
- Added workspace creation and retrieval functionalities.
- Enhanced project model to associate with workspaces.
- Updated project member roles and access control logic.
- Created sign-out page and updated authentication flow.
- Modified header to include navigation to workspaces.
- Updated Prisma schema to include workspace and member models.
- Seed script updated to create demo workspaces and associated members.

app/api/projects/[projectId]/members/[memberId]/route.ts

@@ -0,0 +1,109 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { db } from '@/lib/db';
+import { auth } from '@/lib/auth';
+import { ProjectMemberRole } from '@prisma/client';
+
+type RouteParams = { params: Promise<{ projectId: string; memberId: string }> };
+
+// PATCH /api/projects/[projectId]/members/[memberId] - Update member role
+export async function PATCH(request: NextRequest, { params }: RouteParams) {
+    try {
+        const session = await auth();
+        const { projectId, memberId } = await params;
+
+        if (!session?.user?.id) {
+            return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
+        }
+
+        const project = await db.project.findUnique({
+            where: { id: projectId },
+            include: { members: { where: { userId: session.user.id } } },
+        });
+
+        if (!project) {
+            return NextResponse.json({ error: 'Project not found' }, { status: 404 });
+        }
+
+        const isOwner = project.ownerId === session.user.id;
+        const isAdmin = project.members[0]?.role === ProjectMemberRole.ADMIN;
+
+        if (!isOwner && !isAdmin) {
+            return NextResponse.json({ error: 'Access denied' }, { status: 403 });
+        }
+
+        const body = await request.json();
+        const { role } = body;
+
+        const validRoles = ['ADMIN', 'COMMENTATOR'];
+        if (!validRoles.includes(role)) {
+            return NextResponse.json(
+                { error: 'Invalid role. Must be ADMIN or COMMENTATOR.' },
+                { status: 400 }
+            );
+        }
+
+        const member = await db.projectMember.update({
+            where: { id: memberId },
+            data: { role: role as ProjectMemberRole },
+            include: {
+                user: { select: { id: true, name: true, image: true } },
+            },
+        });
+
+        return NextResponse.json(member);
+    } catch (error) {
+        console.error('Error updating member role:', error);
+        return NextResponse.json(
+            { error: 'Failed to update member role' },
+            { status: 500 }
+        );
+    }
+}
+
+// DELETE /api/projects/[projectId]/members/[memberId] - Remove member
+export async function DELETE(request: NextRequest, { params }: RouteParams) {
+    try {
+        const session = await auth();
+        const { projectId, memberId } = await params;
+
+        if (!session?.user?.id) {
+            return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
+        }
+
+        const project = await db.project.findUnique({
+            where: { id: projectId },
+            include: { members: { where: { userId: session.user.id } } },
+        });
+
+        if (!project) {
+            return NextResponse.json({ error: 'Project not found' }, { status: 404 });
+        }
+
+        const isOwner = project.ownerId === session.user.id;
+        const isAdmin = project.members[0]?.role === ProjectMemberRole.ADMIN;
+
+        const memberToRemove = await db.projectMember.findUnique({
+            where: { id: memberId },
+        });
+
+        if (!memberToRemove) {
+            return NextResponse.json({ error: 'Member not found' }, { status: 404 });
+        }
+
+        const isSelf = memberToRemove.userId === session.user.id;
+
+        if (!isOwner && !isAdmin && !isSelf) {
+            return NextResponse.json({ error: 'Access denied' }, { status: 403 });
+        }
+
+        await db.projectMember.delete({ where: { id: memberId } });
+
+        return NextResponse.json({ success: true, message: 'Member removed' });
+    } catch (error) {
+        console.error('Error removing member:', error);
+        return NextResponse.json(
+            { error: 'Failed to remove member' },
+            { status: 500 }
+        );
+    }
+}