feat: add team generation API endpoints

Add API endpoints for team management:
- POST /api/tournaments/[id]/teams/generate: Generate teams based on configuration
- DELETE /api/tournaments/[id]/teams: Delete all teams
- GET /api/tournaments/[id]/teams: Fetch teams and configuration

Supports multiple generation strategies:
- Random pairing
- ELO-based pairing
- Even matches
- Minimize repeat partnerships

Refs #22

src/app/api/tournaments/[id]/teams/route.ts

@@ -0,0 +1,135 @@
+import { NextResponse } from "next/server"
+import { prisma } from "@/lib/prisma"
+import { canManageTournament } from "@/lib/permissions"
+
+interface RouteParams {
+  params: Promise<{
+    id: string
+  }>
+}
+
+/**
+ * DELETE /api/tournaments/[id]/teams
+ *
+ * Delete all teams for a tournament.
+ * This will also delete any associated schedule.
+ */
+export async function DELETE(_request: Request, { params }: RouteParams) {
+  try {
+    const { id } = await params
+    const tournamentId = parseInt(id)
+
+    if (isNaN(tournamentId)) {
+      return NextResponse.json(
+        { error: "Invalid tournament ID" },
+        { status: 400 }
+      )
+    }
+
+    const permission = await canManageTournament(tournamentId)
+    if (!permission.allowed) {
+      return NextResponse.json(
+        { error: permission.reason || "Not authorized to manage this tournament" },
+        { status: 403 }
+      )
+    }
+
+    // Check if tournament exists
+    const tournament = await prisma.event.findUnique({
+      where: { id: tournamentId },
+      include: {
+        teams: true,
+        rounds: true,
+      },
+    })
+
+    if (!tournament) {
+      return NextResponse.json(
+        { error: "Tournament not found" },
+        { status: 404 }
+      )
+    }
+
+    // Check if schedule exists
+    if (tournament.rounds.length > 0) {
+      return NextResponse.json(
+        { error: "Cannot delete teams while schedule exists. Delete schedule first." },
+        { status: 409 }
+      )
+    }
+
+    // Delete all teams
+    const deletedTeams = await prisma.team.deleteMany({
+      where: { eventId: tournamentId },
+    })
+
+    // Reset team configuration
+    await prisma.event.update({
+      where: { id: tournamentId },
+      data: {
+        teamDurability: "permanent",
+        partnerRotation: "none",
+        allowByes: true,
+      },
+    })
+
+    return NextResponse.json({
+      success: true,
+      deletedTeams: deletedTeams.count,
+    })
+  } catch (error: unknown) {
+    console.error("Error deleting teams:", error)
+    const message = error instanceof Error ? error.message : "Failed to delete teams"
+    return NextResponse.json({ error: message }, { status: 500 })
+  }
+}
+
+/**
+ * GET /api/tournaments/[id]/teams
+ *
+ * Get all teams for a tournament.
+ */
+export async function GET(_request: Request, { params }: RouteParams) {
+  try {
+    const { id } = await params
+    const tournamentId = parseInt(id)
+
+    if (isNaN(tournamentId)) {
+      return NextResponse.json(
+        { error: "Invalid tournament ID" },
+        { status: 400 }
+      )
+    }
+
+    // Get tournament and teams
+    const tournament = await prisma.event.findUnique({
+      where: { id: tournamentId },
+      include: {
+        teams: {
+          include: {
+            player1: true,
+            player2: true,
+          },
+        },
+      },
+    })
+
+    if (!tournament) {
+      return NextResponse.json(
+        { error: "Tournament not found" },
+        { status: 404 }
+      )
+    }
+
+    return NextResponse.json({
+      teams: tournament.teams,
+      teamDurability: tournament.teamDurability,
+      partnerRotation: tournament.partnerRotation,
+      allowByes: tournament.allowByes,
+    })
+  } catch (error: unknown) {
+    console.error("Error fetching teams:", error)
+    const message = error instanceof Error ? error.message : "Failed to fetch teams"
+    return NextResponse.json({ error: message }, { status: 500 })
+  }
+}