Add comprehensive offline help system with fuzzy search

🎯 Enhanced Features:
- Integrated navi, cheat, tldr, and fzf for interactive help
- Custom cheat sheets for PDF analysis, malware analysis, and system utilities
- find-tool command for fuzzy searching through all REMnux tools
- Comprehensive help command with workflows and examples
- Complete offline documentation system

📚 Help System Components:
- help                    - Main help system
- help tools [term]       - Search for tools (fuzzy matching)
- help cheat <tool>       - Show command examples
- help examples           - Browse examples interactively (navi + fzf)
- help pdf/malware/forensics - Analysis workflows
- help --offline          - Verify offline capabilities

🛠️ Tools Added:
- navi: Interactive cheat sheet browser
- cheat: Command-line cheat sheets
- tldr: Quick command examples
- fzf: Fuzzy finder (already included)

All documentation works completely offline with local REMnux docs database
and custom cheat sheets for analysis workflows.

cheatsheets/pdf-analysis.cheat

@@ -0,0 +1,63 @@
+# PDF Analysis Tools
+# Quick reference for analyzing PDF files for malware
+
+% pdf, malware, analysis
+
+# Quick PDF overview - shows suspicious elements
+pdfid.py <pdf_file>
+
+# Detailed PDF structure analysis
+pdf-parser.py <pdf_file>
+
+# Interactive PDF analysis with JavaScript detection
+peepdf -i <pdf_file>
+
+# Force processing of potentially corrupted PDF
+peepdf -f -i <pdf_file>
+
+# Extract specific PDF object
+pdf-parser.py -o <object_id> <pdf_file>
+
+# Hash PDF elements for comparison
+pdf-parser.py -H <pdf_file>
+
+# Export embedded object from PDF
+pdf-parser.py -d <output_file> -f -o <object_id> <pdf_file>
+
+# Flatten PDF (remove JavaScript and active elements)
+pdftk <pdf_file> cat output flattened_<pdf_file>
+
+# Extract embedded files from PDF
+pdftk <pdf_file> unpack_files
+
+# Extract from password-protected PDF
+pdftk <pdf_file> input_pw <password> unpack_files
+
+# Convert PDF to TIFF (safe rendering)
+convert <pdf_file> <output_file>.tiff
+
+# Analyze PDF metadata with Origami
+pdfmetadata <pdf_file>
+
+# Extract PDF streams and objects
+pdfextract <pdf_file>
+
+# Validate PDF structure
+pdfcop <pdf_file>
+
+# Decrypt PDF file
+pdfdecrypt <pdf_file> <output_file>
+
+# Merge multiple PDFs
+qpdf --empty --pages <pdf1> <pdf2> -- <output_file>
+
+# Extract previous versions from PDF
+pdfresurrect <pdf_file>
+
+# Analyze incremental updates in PDF
+pdftool.py <pdf_file>
+
+$ pdf_file: ls *.pdf
+$ object_id: echo "1 2 3 4 5 6 7 8 9 10"
+$ output_file: echo "output"
+$ password: echo "password123"