sync: PDF file upload from private repo

- Add drag-and-drop PDF upload to Quick Capture
- New upload endpoint with size limits (warn 10MB, reject 50MB)
- Add extractFromBuffer method to PaperExtractor
- Visual feedback: drag-over highlight, file preview card

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

app/api/extract/pdf/upload/route.ts

@@ -0,0 +1,104 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { PaperExtractor } from '@/services/typescript/extractors/paper';
+
+export const runtime = 'nodejs';
+
+// Size limits in bytes
+const WARN_SIZE = 10 * 1024 * 1024; // 10MB
+const MAX_SIZE = 50 * 1024 * 1024;  // 50MB
+
+export async function POST(request: NextRequest) {
+  try {
+    const formData = await request.formData();
+    const file = formData.get('file');
+
+    // Validate file presence
+    if (!file || !(file instanceof File)) {
+      return NextResponse.json(
+        { success: false, error: 'PDF file is required' },
+        { status: 400 }
+      );
+    }
+
+    // Validate MIME type
+    if (file.type !== 'application/pdf') {
+      return NextResponse.json(
+        { success: false, error: `Invalid file type: ${file.type}. Only PDF files are accepted.` },
+        { status: 400 }
+      );
+    }
+
+    // Check file size
+    if (file.size > MAX_SIZE) {
+      return NextResponse.json(
+        { success: false, error: `File too large (${Math.round(file.size / 1024 / 1024)}MB). Maximum size is 50MB.` },
+        { status: 413 }
+      );
+    }
+
+    const isLargeFile = file.size > WARN_SIZE;
+
+    // Get buffer from file
+    const buffer = Buffer.from(await file.arrayBuffer());
+
+    // Extract PDF content using PaperExtractor
+    const extractor = new PaperExtractor();
+    const extraction = await extractor.extractFromBuffer(buffer, file.name);
+
+    // Derive title from metadata or filename
+    const title = extraction.metadata.title || file.name.replace(/\.pdf$/i, '');
+
+    // Create node via internal API call
+    // IMPORTANT: Use request.url origin for packaged Tauri app compatibility
+    const nodeApiUrl = new URL('/api/nodes', request.url);
+
+    const createResponse = await fetch(nodeApiUrl.toString(), {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({
+        title,
+        type: 'pdf',
+        // Keep content readable in UI (not the full extracted text)
+        content: `Imported PDF: ${file.name} (${extraction.metadata.pages} pages, ${Math.round(extraction.metadata.text_length / 1000)}k characters)`,
+        // Full extracted text goes in chunk for universal chunking/embedding
+        chunk: extraction.chunk,
+        metadata: {
+          source: 'pdf_upload',
+          original_filename: file.name,
+          pages: extraction.metadata.pages,
+          text_length: extraction.metadata.text_length,
+          extraction_method: extraction.metadata.extraction_method,
+          imported_at: new Date().toISOString(),
+        },
+      }),
+    });
+
+    if (!createResponse.ok) {
+      const errorData = await createResponse.json().catch(() => ({}));
+      throw new Error(errorData.error || `Failed to create node: ${createResponse.status}`);
+    }
+
+    const nodeResult = await createResponse.json();
+
+    if (!nodeResult.success || !nodeResult.data?.id) {
+      throw new Error(nodeResult.error || 'Failed to create node');
+    }
+
+    return NextResponse.json({
+      success: true,
+      nodeId: nodeResult.data.id,
+      title,
+      pages: extraction.metadata.pages,
+      textLength: extraction.metadata.text_length,
+      warning: isLargeFile ? `Large file (${Math.round(file.size / 1024 / 1024)}MB) - processing may take longer` : undefined,
+    });
+
+  } catch (error) {
+    console.error('[PDF Upload API] Error:', error);
+    const message = error instanceof Error ? error.message : 'Failed to process PDF upload';
+    return NextResponse.json(
+      { success: false, error: message },
+      { status: 500 }
+    );
+  }
+}