feat(api): add courts and availability endpoints

Add REST API endpoints for court management and availability:
- GET/POST /api/courts for listing and creating courts
- GET/PUT/DELETE /api/courts/[id] for single court operations
- GET /api/courts/[id]/availability for time slot availability
- GET /api/sites for listing organization sites

Features include organization-based filtering, role-based access control,
premium pricing for evening/weekend slots, and booking conflict detection.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/web/app/api/sites/route.ts

@@ -0,0 +1,70 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { getServerSession } from 'next-auth';
+import { authOptions } from '@/lib/auth';
+import { db } from '@/lib/db';
+
+// GET /api/sites - List sites for user's organization
+export async function GET(request: NextRequest) {
+  try {
+    const session = await getServerSession(authOptions);
+
+    if (!session?.user) {
+      return NextResponse.json(
+        { error: 'Unauthorized' },
+        { status: 401 }
+      );
+    }
+
+    const sites = await db.site.findMany({
+      where: {
+        organizationId: session.user.organizationId,
+        isActive: true,
+      },
+      select: {
+        id: true,
+        name: true,
+        slug: true,
+        address: true,
+        phone: true,
+        email: true,
+        timezone: true,
+        openTime: true,
+        closeTime: true,
+        _count: {
+          select: {
+            courts: {
+              where: {
+                isActive: true,
+              },
+            },
+          },
+        },
+      },
+      orderBy: {
+        name: 'asc',
+      },
+    });
+
+    // Transform to include court count at top level
+    const transformedSites = sites.map((site) => ({
+      id: site.id,
+      name: site.name,
+      slug: site.slug,
+      address: site.address,
+      phone: site.phone,
+      email: site.email,
+      timezone: site.timezone,
+      openTime: site.openTime,
+      closeTime: site.closeTime,
+      courtCount: site._count.courts,
+    }));
+
+    return NextResponse.json(transformedSites);
+  } catch (error) {
+    console.error('Error fetching sites:', error);
+    return NextResponse.json(
+      { error: 'Failed to fetch sites' },
+      { status: 500 }
+    );
+  }
+}