Move docs/ package mirror into document-navigator plugin

Relocate the ~6k-file docs tree from the repo root into
plugins/document-navigator/docs/ so the plugin is self-contained and
portable. docs/superpowers/ (specs and plans) stays at the repo root.

Moved via cp+rm rather than git mv because directory rename() fails with
EPERM on this WSL /mnt DrvFs mount; git rename-detection pairs the
identical-content files at commit time.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

plugins/document-navigator/docs/foundation/barcode/README.md

@@ -0,0 +1,14 @@
+# `barcode`
+
+1-D barcode generation and parsing.
+
+<!-- begin:auto-docs -->
+## Packages in `barcode`
+
+2 packages.
+
+| Package | Description |
+|---|---|
+| [`@suaveplan/barcode`](./barcode/README.md) | Runtime-agnostic 1D barcode generation for seven symbologies — Code 128B, Code 39, EAN-13, EAN-8, UPC-A, UPC-E, and ITF. Outputs inline SVG strings and binary… |
+| [`@suaveplan/qrcode`](./qrcode/README.md) | QR code generation producing SVG, pixel matrix, terminal (Unicode blocks), and data URL representations. Implements QR code versions 1-10, error correction lev… |
+<!-- end:auto-docs -->