The rail was on the right. It now leads the row instead, so the section menu
reads as a conventional left-hand navigation column.
Which side it lands on was never a stylesheet decision: `.app-body` is a flex
row and the aside is simply its first child now, with `.app-main` after it.
The only style change that had to follow is the rail's separator, which moves
from its left edge to its right, plus the collapse tooltip's placement.
The global shell contract in base.css now says this explicitly, so the next
person to move the rail knows the side comes from DOM order rather than from a
rule in that file.
Records the decisions that are not visible from the code alone:
- why section_field has no parent_id, and what reuse that buys;
- that template_field.sort is the single source of display order, and
that repeats and ties are deliberately legal;
- that templates reference library fields rather than copying them, which
is what makes a rename propagate;
- that TiDB parses FOREIGN KEY and ignores it, so the integrity lives in
the application layer.
Also adds the API table, the frontend route table, and the seed script.
govin