Add per-worker stats page with cumulative work and luck

Expose ckpool's per-worker cumulative shares via patch 0004, add a
WorkerDetailPage with hashrate, status, best share with per-worker luck
(bestever/shares*100), and total work with pool share percentage.
Worker names are now clickable in MinersTable and UserDetailPage.
Also centers numeric columns below their headers.

ui/src/App.svelte

@@ -10,6 +10,7 @@
   import BlocksTable from "./lib/BlocksTable.svelte";
   import BestShares from "./lib/BestShares.svelte";
   import UserDetailPage from "./lib/UserDetailPage.svelte";
+  import WorkerDetailPage from "./lib/WorkerDetailPage.svelte";
   import BlockFoundAnimation from "./lib/BlockFoundAnimation.svelte";
 
   onMount(() => {
@@ -32,6 +33,8 @@
         <div class="stat-sub bad">{snap.error}</div>
       {/if}
     </div>
+  {:else if selection.worker}
+    <WorkerDetailPage />
   {:else if selection.user}
     <UserDetailPage />
   {:else}