Fix BPM/track-length row overflowing right edge, and verify 2-digit minutes

The row had nothing constraining its width -- every other line in this
column is a Marquee, which enforces its own declared width, but this
plain Row had no such limit, so any estimation error in the
character-count-based width guess (pixlet has no way to measure
rendered text width from Starlark) silently overflowed the column
instead of being clipped. Wrapped in a Box(width=text_width, height=6)
to hard-clip it.

The height was not optional: a bare Box(width=...) with no height
"expand[s] to fill all available space" (pixlet's own docs), and inside
this Column's main_align="space_between", that meant the row silently
grabbed nearly all remaining height, squeezing the progress bar below
it out of view -- same bug class as the earlier time_temp centering
fix (a flexible/expanding child stealing vertical space), just via
Box's implicit expand-when-unconstrained behavior this time instead of
Row's explicit expanded=True. Caught by tracing pixel colors down the
render rather than trusting a glance: the row's text was present, just
not where expected, and the progress bar's color was missing from the
frame entirely.

Verified two-digit minutes work correctly: a minimal standalone test
replicating this exact construction with a hardcoded "12:34" renders
right-aligned with no overflow, and the real (unmodified) app was
independently re-verified live against two different real tracks,
confirming the fix holds with genuine data, not just a synthetic case.

subwave_nowplaying.star

@@ -378,11 +378,41 @@ def main(config):
         bpm_width = int(len(list(now["bpm"].codepoints())) * 3.9)
         length_width = int(len(list(now["track_length"].codepoints())) * 3.9)
         gap = max(0, text_width - bpm_width - length_width)
-        children.append(render.Row(children = [
-            render.Text(now["bpm"], font = "tom-thumb", color = colors["meta"]),
-            render.Box(width = gap, height = 1),
-            render.Text(now["track_length"], font = "tom-thumb", color = colors["meta"]),
-        ]))
+
+        # Wrapped in a Box(width=text_width, height=6) to hard-clip it --
+        # every other line in this column is a Marquee, which enforces its
+        # own declared width, but this Row had nothing constraining it, so
+        # any estimation error (the 3.9px/char figure is an estimate, not
+        # an exact measurement -- pixlet has no way to measure rendered
+        # text width from Starlark) silently overflowed the column instead
+        # of being clipped, bleeding past the right edge. Also what
+        # actually supports two-digit minutes/long durations safely: if
+        # bpm_width + length_width ever exceeds text_width (gap floors at
+        # 0, so they'd butt up with no space between), this still caps the
+        # total at text_width rather than spilling out.
+        #
+        # height=6 (tom-thumb's own line height) is required, not
+        # optional: a bare Box(width=...) with no height "expand[s] to
+        # fill all available space" (pixlet's own docs) -- inside this
+        # Column's main_align="space_between", that meant the row silently
+        # grabbed nearly the entire remaining height, squeezing the
+        # progress bar below it off-screen. Same bug class as the earlier
+        # time_temp centering fix (a flexible/expanding child stealing
+        # vertical space it wasn't meant to use), just via Box's own
+        # implicit expand-when-unconstrained behavior this time instead of
+        # Row's explicit `expanded=True`. Caught by literally tracing
+        # pixel colors down a column of the render rather than trusting a
+        # visual glance -- the row's text was there, just not where
+        # expected, and the progress bar's color was nowhere in the frame.
+        children.append(render.Box(
+            width = text_width,
+            height = 6,
+            child = render.Row(children = [
+                render.Text(now["bpm"], font = "tom-thumb", color = colors["meta"]),
+                render.Box(width = gap, height = 1),
+                render.Text(now["track_length"], font = "tom-thumb", color = colors["meta"]),
+            ]),
+        ))
 
     if progress != None:
         children.append(_progress_bar(progress["fraction"], colors, width = text_width, height = 2 * scale))