Add markdown wiki with 473 pages and zk browser

Generate interlinked wiki from master inventory: 397 tool pages,
15 workflow pages, 27 recipe pages, 33 category pages, plus index.
All pages use [[wiki-links]] for cross-navigation between tools,
workflows, recipes, and categories (1782 links total).

Install zk for interactive browsing with fzf search, tag filtering,
and backlink discovery. Add 'fhelp wiki' command and Makefile target.

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

data/generated/wiki/tools/pdftk.md

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+# pdftk
+> Manipulate PDF files — merge, split, flatten, encrypt, and extract embedded content
+
+**Category:** [[categories/analyze-documents-pdf|Analyze Documents > PDF]] | **Tier:** Rich (FOR610)
+**Docs:** [https://docs.remnux.org/discover-the-tools/analyze+documents/pdf](https://docs.remnux.org/discover-the-tools/analyze+documents/pdf)
+
+## Usage
+```bash
+pdftk input.pdf cat output output.pdf flatten
+pdftk input.pdf unpack_files
+```
+
+## Related Tools
+- [[tools/origamindee|origamindee]] — Parse, modify, generate PDF files.
+- [[tools/pdf-parser|pdf-parser.py]] — Parse PDF structure, locate objects, extract content, and se
+- [[tools/pdfid|pdfid.py]] — Scan PDF files for suspicious keywords like /JavaScript, /Op
+- [[tools/pdfresurrect|pdfresurrect]] — Extract and analyze previous versions from PDF files
+- [[tools/pdftool|pdftool.py]] — Analyze PDF incremental updates
+
+## FOR610
+**Sections:** 3
+
+#pdf #manipulation #extraction