Anchored h1/h2s carry data-line (markdown source line, top-level
headings only) and h2s get dimmed section pens that open the page
editor at that section. Editor scroll sync is now piecewise-linear
keyed on those anchors: the page follows the cursor (fractional,
wrap-aware, fixed window anchor; editor scroll no longer drives it),
the editor follows page scroll with a progress-based viewport anchor,
so document ends line up exactly in both directions. The editor always
follows the URL — fetch-navigation retargets it — with unsaved text
stashed per path for the session and restored on return. Banner pen
removed (the tab stays in the shell); top-right order is now
analytics, site settings, login/logout.