fix: security hardening, UI fixes, and validation improvements

- Fix header nav overflow by switching to lg: breakpoint with tighter gaps
- Fix file upload path traversal by whitelisting allowed folders and extensions
- Fix BookingModal using hardcoded content instead of DB-backed data
- Add input length validation on public master-class registration API
- Add ID validation on team member and reorder API routes
- Fix BookingModal useCallback missing groupInfo/contact dependencies
- Improve admin news date field to use native date picker
- Add missing Мастер-классы and Новости cards to admin dashboard

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/app/api/admin/team/[id]/route.ts

@@ -4,9 +4,18 @@ import { revalidatePath } from "next/cache";
 
 type Params = { params: Promise<{ id: string }> };
 
+function parseId(raw: string): number | null {
+  const n = Number(raw);
+  return Number.isInteger(n) && n > 0 ? n : null;
+}
+
 export async function GET(_request: NextRequest, { params }: Params) {
   const { id } = await params;
-  const member = getTeamMember(Number(id));
+  const numId = parseId(id);
+  if (!numId) {
+    return NextResponse.json({ error: "Invalid ID" }, { status: 400 });
+  }
+  const member = getTeamMember(numId);
   if (!member) {
     return NextResponse.json({ error: "Not found" }, { status: 404 });
   }
@@ -15,15 +24,23 @@ export async function GET(_request: NextRequest, { params }: Params) {
 
 export async function PUT(request: NextRequest, { params }: Params) {
   const { id } = await params;
+  const numId = parseId(id);
+  if (!numId) {
+    return NextResponse.json({ error: "Invalid ID" }, { status: 400 });
+  }
   const data = await request.json();
-  updateTeamMember(Number(id), data);
+  updateTeamMember(numId, data);
   revalidatePath("/");
   return NextResponse.json({ ok: true });
 }
 
 export async function DELETE(_request: NextRequest, { params }: Params) {
   const { id } = await params;
-  deleteTeamMember(Number(id));
+  const numId = parseId(id);
+  if (!numId) {
+    return NextResponse.json({ error: "Invalid ID" }, { status: 400 });
+  }
+  deleteTeamMember(numId);
   revalidatePath("/");
   return NextResponse.json({ ok: true });
 }

src/app/api/admin/team/reorder/route.ts

@@ -5,8 +5,8 @@ import { revalidatePath } from "next/cache";
 export async function PUT(request: NextRequest) {
   const { ids } = await request.json() as { ids: number[] };
 
-  if (!Array.isArray(ids) || ids.length === 0) {
-    return NextResponse.json({ error: "ids array required" }, { status: 400 });
+  if (!Array.isArray(ids) || ids.length === 0 || !ids.every((id) => Number.isInteger(id) && id > 0)) {
+    return NextResponse.json({ error: "ids must be a non-empty array of positive integers" }, { status: 400 });
   }
 
   reorderTeamMembers(ids);

src/app/api/admin/upload/route.ts

@@ -3,12 +3,15 @@ import { writeFile, mkdir } from "fs/promises";
 import path from "path";
 
 const ALLOWED_TYPES = ["image/jpeg", "image/png", "image/webp", "image/avif"];
+const ALLOWED_EXTENSIONS = [".jpg", ".jpeg", ".png", ".webp", ".avif"];
+const ALLOWED_FOLDERS = ["team", "master-classes", "news", "classes"];
 const MAX_SIZE = 5 * 1024 * 1024; // 5MB
 
 export async function POST(request: NextRequest) {
   const formData = await request.formData();
   const file = formData.get("file") as File | null;
-  const folder = (formData.get("folder") as string) || "team";
+  const rawFolder = (formData.get("folder") as string) || "team";
+  const folder = ALLOWED_FOLDERS.includes(rawFolder) ? rawFolder : "team";
 
   if (!file) {
     return NextResponse.json({ error: "No file provided" }, { status: 400 });
@@ -28,8 +31,14 @@ export async function POST(request: NextRequest) {
     );
   }
 
-  // Sanitize filename
-  const ext = path.extname(file.name) || ".webp";
+  // Validate and sanitize filename
+  const ext = path.extname(file.name).toLowerCase() || ".webp";
+  if (!ALLOWED_EXTENSIONS.includes(ext)) {
+    return NextResponse.json(
+      { error: "Invalid file extension" },
+      { status: 400 }
+    );
+  }
   const baseName = file.name
     .replace(ext, "")
     .toLowerCase()

src/app/api/master-class-register/route.ts

@@ -6,21 +6,24 @@ export async function POST(request: Request) {
     const body = await request.json();
     const { masterClassTitle, name, instagram, telegram } = body;
 
-    if (!masterClassTitle || typeof masterClassTitle !== "string") {
+    if (!masterClassTitle || typeof masterClassTitle !== "string" || masterClassTitle.length > 200) {
       return NextResponse.json({ error: "masterClassTitle is required" }, { status: 400 });
     }
-    if (!name || typeof name !== "string" || !name.trim()) {
-      return NextResponse.json({ error: "name is required" }, { status: 400 });
+    if (!name || typeof name !== "string" || !name.trim() || name.length > 100) {
+      return NextResponse.json({ error: "name is required (max 100 chars)" }, { status: 400 });
     }
-    if (!instagram || typeof instagram !== "string" || !instagram.trim()) {
+    if (!instagram || typeof instagram !== "string" || !instagram.trim() || instagram.length > 100) {
       return NextResponse.json({ error: "Instagram аккаунт обязателен" }, { status: 400 });
     }
+    if (telegram && (typeof telegram !== "string" || telegram.length > 100)) {
+      return NextResponse.json({ error: "Telegram too long" }, { status: 400 });
+    }
 
     const id = addMcRegistration(
-      masterClassTitle.trim(),
-      name.trim(),
-      instagram.trim(),
-      telegram && typeof telegram === "string" ? telegram.trim() : undefined
+      masterClassTitle.trim().slice(0, 200),
+      name.trim().slice(0, 100),
+      instagram.trim().slice(0, 100),
+      telegram && typeof telegram === "string" ? telegram.trim().slice(0, 100) : undefined
     );
 
     return NextResponse.json({ ok: true, id });