Let a bot take any colour

A bot's identity was one of seven hues, and the hue picked both its colour
and its stone shape. Now its colour is free and its stone is its own:

- `bots.color` holds any `#rrggbb`, `bots.stone` the flat-cut shape it's
  drawn on. `bots.hue` stays as the palette column they replaced, read only
  as a fallback; `src/scripts/move-bot-colour-to-owners.ts` backfills an
  install from it (safe to rerun).
- `src/utils/bot-color.ts` is the only place a colour is validated or
  resolved (`resolveBotColor`/`resolveBotStone` carry the old hue forward,
  `botColorNeedsPaperFace` flips the eyes to paper on a very dark body), and
  `src/utils/bot-stone-props.ts` gives every row its props, so a row saved
  before this still renders as it did.
- `BotStone` takes the colour as the body's SVG `fill`, the one documented
  exception to the token rule: an arbitrary hex has no token to point at.
  `UnreadDot` follows it.
- The picker keeps the palette tiles (still shape and colour together) and
  adds a native swatch and a hex field, so a custom colour keeps its stone.
  Same place as before: the header avatar's modal and Settings > Bots, for
  crew managers. The coordinator stays hue-less.
- A recolour reaches other open tabs through `pushBotUpdated`.

src/utils/bot-stone-props.ts

@@ -0,0 +1,34 @@
+import type { BotStoneShape } from "@/src/dict/bot-dict";
+import { resolveBotColor, resolveBotStone } from "./bot-color";
+
+type Params = {
+    /**
+     * The bot's own colour. Null or missing for the coordinator.
+     */
+    color?: string | null;
+    stone?: string | null;
+    /**
+     * The historical palette hue, only for a bot saved before colours were
+     * free. Rows from otherwise-typed queries select it as `bot_hue`.
+     */
+    hue?: string | null;
+};
+
+type BotStoneProps = {
+    color: string | null;
+    stone: BotStoneShape;
+};
+
+/**
+ * The stone props for a bot row: which colour to fill it with and which
+ * shape to draw, whether the row carries the new columns or only the
+ * palette hue they replaced. Every `<BotAvatar color={...} stone={...} />`
+ * call site goes through this, so a row saved before colours were free
+ * still renders as it did.
+ */
+export default function botStoneProps({ color, stone, hue }: Params): BotStoneProps {
+    return {
+        color: resolveBotColor({ color, hue }),
+        stone: resolveBotStone({ stone, hue }),
+    };
+}