perf(gallery): link each script instead of inlining it; LF-pin generated files

Detail pages embedded the full syntax-highlighted script (farm-tractor:
419 KB of HTML for a 165 KB script), so committed gallery HTML was 20.6 MB,
every script edit rewrote its page, and 274 commits had produced ~5,000 HTML
blobs, the largest share of history growth (and of every plugin install,
since the plugin source is the repo root).

- build_gallery.py: the Source section is now the script path plus a
  "View the script on GitHub" (blob) link. Removed the build-time tokenize
  highlighter, the code-view CSS and the collapse/copy JS for it; the
  #source jump link still resolves. A page no longer changes when only its
  script does.
- All generated files are written with newline="\n", and .gitattributes pins
  *.html, *.css and *.py to LF, so a Windows checkout without
  core.autocrlf=true does not trip the drift gate.

Measured after regeneration: detail pages median 30 KB, max 48.8 KB
(fern-mossy-rock), gallery HTML total 4.59 MB (was 20.6 MB);
134 files, -376k lines. check_site_links on the staged _site: 135 pages,
0 failures; check_gallery_images ok.

Closes #343

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: TMHSDigital

.gitattributes

@@ -2,6 +2,11 @@
 # do not churn gallery.json, plugin.json, or skill files.
 *.json text eol=lf
 *.md text eol=lf
+# Generated gallery HTML/CSS and Python stay LF too: build_gallery.py writes
+# LF, so a Windows checkout with core.autocrlf=false must not see drift.
+*.html text eol=lf
+*.css text eol=lf
+*.py text eol=lf
 
 # Binary. Gallery stills and any future .blend fixtures.
 *.webp binary