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/types/index.ts

@@ -83,6 +83,8 @@ export type CronJobWithNames = BUN_SQLITE_COBBLE_CRON_JOBS & {
     bot_name?: string | null;
     bot_kind?: string | null;
     bot_hue?: string | null;
+    bot_color?: string | null;
+    bot_stone?: string | null;
     bot_face?: string | null;
     bot_image_media_id?: number | null;
     workspace_name?: string | null;
@@ -96,6 +98,8 @@ export type TaskWithNames = BUN_SQLITE_COBBLE_TASKS & {
     bot_name?: string | null;
     bot_kind?: string | null;
     bot_hue?: string | null;
+    bot_color?: string | null;
+    bot_stone?: string | null;
     bot_face?: string | null;
     bot_image_media_id?: number | null;
     workspace_name?: string | null;
@@ -160,6 +164,8 @@ export type WorkspaceActivityItem = BUN_SQLITE_COBBLE_BOT_SESSIONS & {
     bot_name?: string | null;
     bot_image_media_id?: number | null;
     bot_hue?: string | null;
+    bot_color?: string | null;
+    bot_stone?: string | null;
     bot_face?: string | null;
 };
 
@@ -275,6 +281,12 @@ export type BotUpdatedData = {
      * change). A workspace's crew drops a bot that's no longer in it.
      */
     workspace_ids?: number[];
+    /**
+     * Its colour and stone, when the push read them (a recolour, or any bot
+     * change): every rail row and avatar takes them without a reload.
+     */
+    color?: string | null;
+    stone?: string | null;
 };
 
 /**