feat: one California is the product, not a flag

Behind `?one=1` the merged board was something a visitor could not find
and did not get: the site still landed on the Bay Area, the left column
still offered two other boards, and clicking one still tore the board
down and built another. The board existed and the product did not change.

A bare URL is now one California. `?city=sf` and `?city=socal` still get
the dedicated boards, unchanged and on purpose — twenty-nine capture
guards and the `bay-area` and `socal` budget cells aim at those boards by
name and assert the `data-board` they land on, and a metro id falling
back to the merged board would not degrade them, it would make them
silently measure something else. `?one=0` forces the old arrangement, and
both `california` budget cells now pass it: their caps are the plain
state board's 440,000, and without it they would measure the merged board
that `california-one` already covers.

Also `CALIFORNIA.md`: what a single cohesive California is still missing,
measured rather than listed. Every district on the board by the latitude
of its centre is 1 / 23 / 26 / 1 / 2 / 54 across 32-37 N and **zero above
38 N** — 107 districts, 103 of them in two clusters four hundred
kilometres apart, and four hundred and fifty kilometres of northern
California with not one building on it. Eight airports, all Bay or LA.
Two ports, both in San Pedro Bay. Two freeways of twelve vertices each
across a thousand kilometres of state.

The scale is not the problem and the file says so first: the board is
32.50-42.05 N and -124.50 to -114.00 W at 1,919 m to the unit, every
feature on its real coordinate, nothing schematic. It is not too small.
It is empty.

TODO.md

@@ -851,3 +851,30 @@ Two pieces, in this order:
 
 **Do not do either before the relief ramp is judged**, since both are tuned
 against how the ground looks and the ramp changes that. It landed at `d6dc307`.
+
+## One California is the default now — two consumers that follow it
+
+Landed 2026-08-24. A bare `tera.lumbridgecorp.com` is the merged board;
+`?city=sf` and `?city=socal` still get the dedicated boards unchanged, because
+twenty-nine capture guards and two budget cells assert the `data-board` they land
+on and a metro id that silently fell back to the merged board would make them
+measure something else. `?one=0` forces the old three-board arrangement.
+
+Both `california` budget cells were pinned to `?one=0` in the same change: their
+caps are the plain state board's 440,000, and left alone they would have measured
+the merged board — passing, while `california-one` measured the same board and
+nobody watched the other.
+
+**The marketing imagery has not followed, and it should.** `shots.mjs` and
+`films.mjs` build `?city=${shot.city ?? "california"}&handover=0`, so every shot
+that does not name a city now photographs the merged board rather than the plain
+state tier. That is the right picture of the product and the wrong thing to have
+happen silently — the captions were written against a board with no cities on it,
+and `scripts/check-chapter-identity.mjs` does not check prose. Re-shoot with
+`npm run refresh`, then read the captions against what came back; `TODO.md`
+already records that four captions were falsified by engine changes once before
+and that nothing catches it.
+
+The content programme this opens up — what a single cohesive California is still
+missing, and in what order — is **`CALIFORNIA.md`**, kept separate because none
+of it needs a new mechanism and all of it can be worked in parallel.