haml's '=' escapes the output, so '= image_tag …' rendered the literal
'<img src=…>' text on the page instead of an actual <img> tag. Use '!='
to emit unescaped HTML — matches the surrounding '!= stylesheet_link_tag'
pattern in the same template.

../images/fork.png is a relative path that resolves to /images/fork.png
from /tech/index.html. On github.io that accidentally hit utensil.github.io's
user-page /images/fork.png; on tngl.sh there's no parent user page, so it
404'd. image_tag respects http_prefix=/tech/ and emits /tech/images/fork.png.

tzinfo gem's ZoneinfoDataSource only checks hardcoded search_path
(/usr/share/zoneinfo, /usr/share/lib/zoneinfo, /etc/zoneinfo) — TZDIR
env is ignored. Locate the nix-store tzdata (filter on '*-tzdata*' to
skip Python's lib/zoneinfo) and symlink /usr/share/zoneinfo to it.
Keep TZDIR as belt+suspenders for tzset(3) consumers.

Previous TZDIR fix found Python 3.13's lib/python3.13/zoneinfo before the
tzdata package — those dirs contain the Python module, not POSIX zoneinfo
files, so tzinfo gem got 'No source of timezone data could be found'.
Filter the find to '*-tzdata*' paths + sanity-check Etc/UTC exists.

First Spindle run failed at config.rb:74 (Middleman 'Time.zone =' /
'set :timezone' line) with TZInfo::DataSources::ZoneinfoDirectoryNotFound.
tzinfo's default search path is ['/usr/share/zoneinfo', '/etc/zoneinfo'];
nixery's tzdata package puts zoneinfo under /nix/store/<hash>-tzdata-XXXX/
share/zoneinfo. Locate it via find + export TZDIR before the build step.

Empty commit to fire the .tangled/workflows/render.yml on the freshly-linked
Spindle for utensil.tngl.sh/tech.