User page: hash-routed view, full block hash, aligned rewards

The per-user view was an overlay modal, but users asked for an
actual page — focused, scrollable, addressable. Replace the modal
with a hash-routed page: selectUser(addr) sets window.location.hash
to #/user/<addr> and a hashchange listener syncs the selection
state back, so browser back/forward and direct-link refresh all
work without a routing library. App renders the dashboard or the
UserDetailPage based on selection.user.

Make the clickable BTC addresses in the Miners table obviously
interactive: accent colour, always-on dashed underline, brighter on
hover/focus. The previous styling rendered them as dim static text
with a hover underline, so it wasn't obvious they were links.

BlocksTable: show the full 64-char block hash as a link to
mempool.space (auto-picks testnet4/signet based on snap.chain).
word-break: break-all keeps the hash from blowing out the column
width. Reward column is split into a tabular-num number span and a
dim 0.75em "BTC" unit span, matching the Block reward tile in the
overview, so numbers line up cleanly across rows.

ui/src/App.svelte

@@ -1,13 +1,14 @@
 <script lang="ts">
   import { onMount } from "svelte";
   import { connect, snap } from "./stores/snapshot.svelte";
+  import { selection } from "./stores/selection.svelte";
   import Header from "./lib/Header.svelte";
   import PoolOverview from "./lib/PoolOverview.svelte";
   import HashrateChart from "./lib/HashrateChart.svelte";
   import MinersTable from "./lib/MinersTable.svelte";
   import BlocksTable from "./lib/BlocksTable.svelte";
   import BestShares from "./lib/BestShares.svelte";
-  import UserDetailModal from "./lib/UserDetailModal.svelte";
+  import UserDetailPage from "./lib/UserDetailPage.svelte";
   import BlockFoundAnimation from "./lib/BlockFoundAnimation.svelte";
 
   onMount(() => {
@@ -26,6 +27,8 @@
         <div class="stat-sub bad">{snap.error}</div>
       {/if}
     </div>
+  {:else if selection.user}
+    <UserDetailPage />
   {:else}
     <PoolOverview />
     <HashrateChart />
@@ -35,7 +38,6 @@
   {/if}
 </main>
 
-<UserDetailModal />
 <BlockFoundAnimation />
 
 <style>