Loose .md/.txt/.log files rendered as forced-download links in the gallery
and downloaded (or showed raw) when opened. Now they open in a readable
in-booth page via the existing /b/<name>/view route:
- .md -> rendered HTML (Python-Markdown: fenced code, tables, sane lists),
styled in an Australis .markdown-body with the viewer chrome;
- .txt/.log -> preformatted <pre> text view.
The gallery links docs to the viewer (📄) instead of a download; the view
page keeps a ⬇ (?dl=1) for saving. Files over 2 MB hand back raw. New
markdown dep (optional-import: degrades .md to text view if absent).
booth_image_view -> booth_view_file (now handles image + doc + raw-fallback).
9 new tests, suite 44 passing; deployed + verified live on nh3-dev :8090.
vh
315faac4b5