Replaces the plain python3 http.server + one-shot make blog with a
watcher pipeline: chokidar regenerates HTML on MD/template changes,
browser-sync serves the site and reloads the browser on rendered-asset
changes. First run downloads both via npx; subsequent runs are instant.
Preflight checks for npx and pandoc. Port arg parsing is tolerant of
legacy --drafts flag ordering (drafts are always included now, since
that's what the dev loop actually wants).
Cleanup trap kills the watcher on exit so re-runs don't leave orphans.
New post on reqwest HTTP/2 window tuning and request hedging
(Dean & Barroso's "The Tail at Scale" applied to DNS forwarding).
Covers DoH forwarding p99 improvement and cold recursive
resolution from 2.3s to 538ms.
Also adds blog build infrastructure: index generation script,
draft preview server, hero metrics/before-after CSS, and
normalizes date format across existing posts.
