Side length per format: team table with songs a side; palette control

Side length "at most" per format is now the table the team supplied
(October 2026, from recordplayerexpert.com, songs counted at an average
4:32): 12" 22 / 15 min, 10" 15 / 12 min, 7" 7 / 5 min at 33 1/3 / 45 rpm.
Changes against the earlier microcut.studio figures: 10" 33 1/3 16 -> 15,
10" 45 11 -> 12, 7" 45 6 -> 5. The comfortable column stays the lower end
of microcut.studio's ranges.

- artist-platform.md: table with a songs column, both sources, and the
  three formats where cutting rooms disagree (10" 45 is now more generous
  than microcut.studio and Diggers Factory) as re-check points for the
  cutting engineer
- artist-order.html: LIM and the side-length table (songs column, sources)
- make-a-record.html: LIM; format cards show the at-most time and about
  how many songs a side; step 2 hint adds the songs; the last control in
  each colour row is now a labelled "Palette" pill with a colour wheel,
  showing the chosen colour and "Your colour" when a custom colour is set

docs/artist-platform.md

@@ -143,23 +143,33 @@ Transparency rules, so the word means something:
 ### Side length per format
 
 The audio check compares each side with the format's limit. Until the
-cutting engineer sets CNX's own figures, the demo uses published
-cutting-room guidance (checked October 2026):
+cutting engineer sets CNX's own figures, the demos use these (October
+2026):
 
-| Format | Comfortable | At most |
-|---|---|---|
-| 12", 33⅓ rpm | 18 min | 22 min |
-| 12", 45 rpm | 12 min | 15 min |
-| 10", 33⅓ rpm | 12 min | 16 min |
-| 10", 45 rpm | 8 min | 11 min |
-| 7", 33⅓ rpm | 5 min | 7 min |
-| 7", 45 rpm | 4.5 min | 6 min |
+| Format | Comfortable | At most | Songs a side, at most |
+|---|---|---|---|
+| 12", 33⅓ rpm | 18 min | 22 min | ~4.9 |
+| 12", 45 rpm | 12 min | 15 min | ~3.3 |
+| 10", 33⅓ rpm | 12 min | 15 min | ~3.3 |
+| 10", 45 rpm | 8 min | 12 min | ~2.6 |
+| 7", 33⅓ rpm | 5 min | 7 min | ~1.5 |
+| 7", 45 rpm | 4.5 min | 5 min | ~1.1 |
 
-Source: the microcut.studio format guide
-(https://microcut.studio/guides/vinyl-format-guide-12-10-7/, lower end of
-each range). Diggers Factory lists hard maxima of 22, 12, 17, 10, 6 and 5
-minutes for the same formats (stricter on 12" at 45 rpm), and A to Z Media
-14 to 18 minutes as ideal on a 12" LP. Loud or bass-heavy music needs
+**At most** and **songs** are the table the team supplied in October
+2026, from recordplayerexpert.com ("How much can a vinyl record hold",
+https://recordplayerexpert.com/vinyl-record-capacity, checked October
+2026), which counts songs at an average length of 4:32. **Comfortable**
+is the lower end of each range in the microcut.studio format guide
+(https://microcut.studio/guides/vinyl-format-guide-12-10-7/).
+
+The published cutting-room figures disagree with the at-most column in
+three places, so treat those as re-check points for the cutting engineer:
+10" at 33⅓ rpm (15 min here; microcut.studio up to 16, Diggers Factory
+17), 10" at 45 rpm (12 min here; microcut.studio 11, Diggers Factory 10,
+so this table is the most generous) and 7" at 45 rpm (5 min here, as
+Diggers Factory; microcut.studio 6). Diggers Factory lists hard maxima of
+22, 12, 17, 10, 6 and 5 minutes for the six formats (stricter on 12" at
+45 rpm), and A to Z Media 14 to 18 minutes as ideal on a 12" LP. Loud or bass-heavy music needs
 shorter sides: Diggers Factory's dance-music figures are about 60 % of its
 standard ones (11:27 against 19:23 on a 12" LP), which the demo applies as
 a factor of 0.6. The engineer check, not this table, decides whether a