detekt: sector indices as a table, not a when

MagicNumber's ignore list is -1/0/1/2, so the `3 ->` and `4 ->` branch
labels were findings. A lookup table has no literals to flag, and it is the
form colors.ts already uses — the two now read as the same function rather
than as two people's idea of it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

android/app/src/main/java/com/fabledsword/thoughtsync/ui/DerivedTint.kt

@@ -261,15 +261,19 @@ private fun hslToArgb(
     val sector = hue / HUE_SECTOR_DEGREES
     val second = chroma * (1.0 - abs(sector % TWO - 1.0))
     val match = lightness - chroma / TWO
-    val (red, green, blue) =
-        when (sector.toInt()) {
-            0 -> Triple(chroma, second, 0.0)
-            1 -> Triple(second, chroma, 0.0)
-            2 -> Triple(0.0, chroma, second)
-            3 -> Triple(0.0, second, chroma)
-            4 -> Triple(second, 0.0, chroma)
-            else -> Triple(chroma, 0.0, second)
-        }
+    // The six hue sectors, as a table rather than a `when` — which is also the form
+    // colors.ts uses, so the two read as the same function rather than as two people's
+    // idea of it. `sector` is in [0, 6) because the hue it came from is in [0, 360).
+    val ramps =
+        listOf(
+            Triple(chroma, second, 0.0),
+            Triple(second, chroma, 0.0),
+            Triple(0.0, chroma, second),
+            Triple(0.0, second, chroma),
+            Triple(second, 0.0, chroma),
+            Triple(chroma, 0.0, second),
+        )
+    val (red, green, blue) = ramps[sector.toInt()]
     return (ALPHA_OPAQUE shl ALPHA_BIT_SHIFT) or
         (channelByte(red + match) shl RED_BIT_SHIFT) or
         (channelByte(green + match) shl GREEN_BIT_SHIFT) or