feat: 2026 UI overhaul, stability fixes, and NVIDIA NIM support

- Overhauled frontend with 2026 hacking HUD aesthetic (neon colors, glassmorphism)
- Added native support for NVIDIA NIM as a Tier 2 provider
- Fixed critical backend crashes in autonomous_agent.py and knowledge_processor.py
- Updated Kali sandbox build to Go 1.26 and fixed health check reliability
- Integrated Space Grotesk and JetBrains Mono fonts

backend/core/knowledge_processor.py

@@ -177,7 +177,7 @@ class KnowledgeProcessor:
 
     def _extract_text_pdf(self, file_path: Path) -> str:
         """Extract text from PDF."""
-        if not HAS_PYPDKF2:
+        if not HAS_PYPDF2:
             logger.warning("PyPDF2 not installed - PDF extraction unavailable. Install: pip install PyPDF2")
             # Try reading as text fallback
             try: