web: read the photo's own size off the row under it

The row below the photo carried CLEAR, OPEN and SAVE ORIGINAL but never said how
big the picture was, so the only way to learn the resolution was to open the
export menu and read the hint there. The size now leads that row, before CLEAR:
the file's own pixels turned by the quarter turn and cut by an applied crop, so
it is the number an export at the photo's own size writes. A live crop does not
move it (nothing is cut yet), STRAIGHTEN never does (the rotated rectangle is
fitted back inside the same pixels), and the guest tier's 2048 cap is still only
announced in the export menu where the file itself is capped.

Verified end to end in photo-dims-probe.cjs: 2400x1800 opens as "2400 × 1800",
a 90 deg turn reads 1800 × 2400, an applied 1:1 crop reads 1800 × 1800, and the
export writes exactly that file.

docker/frontend/src/styles/app.css

@@ -459,6 +459,9 @@ input[type="range"] { width: 100%; accent-color: var(--accent); }
   box-shadow: var(--shadow);
 }
 .stage .toolbar { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; justify-content: center; }
+/* The photo's own size, first in that row: monospaced so the digits do not
+   shuffle the buttons sideways while a crop is being dragged. */
+.stage .toolbar .dims { font-family: var(--mono); white-space: nowrap; }
 .err { color: var(--danger); font-size: 12px; max-width: 520px; text-align: center; }
 
 /* --- auth dialog -------------------------------------------------------- */