Unify best-share semantics across leaderboard / miners / user page

BestShares read worker.bestdiff for its "Best (round)" column,
while MinersTable used client.bestdiff for online workers (and
worker.bestdiff only as a fallback for offline ones). ckpool
resets *both* fields in reset_bestshares() when the pool finds a
block, but reconnect / timing can leave them briefly divergent,
so the same worker could show different values in the two tables.

Switch every "session best" display to the same computation:

    max(client.bestdiff, worker.bestdiff)

…picking whichever is currently higher. Relabel the column from
"Best (round)" to "Best (session)" in MinersTable, BestShares, and
UserDetailPage so the meaning matches the value. UserDetailPage's
per-user summary tile used to show the user's round-best as a
sub-line; drop it, since it contradicts the "session" framing at
the row level.

Net effect: scroll between the leaderboard and the miners table
and the same worker's best-share number stays put.

ui/src/lib/BestShares.svelte

@@ -1,18 +1,31 @@
 <script lang="ts">
   import { snap } from "../stores/snapshot.svelte";
   import { formatDifficulty } from "../format";
+  import type { StratumClient } from "../types";
 
-  // Top 10 workers by all-time best share. `bestever` requires the
-  // Kamado ckpool patch (0001-expose-bestever-in-runtime-json.patch)
-  // — on an unpatched ckpool it will be zero everywhere and we fall
-  // back to the current round's best diff.
+  // Join client data into worker rows so the "session best" column
+  // matches what the Miners table renders for the same worker.
+  // ckpool's reset_bestshares() zeroes both worker.best_diff and
+  // client.best_diff when the pool finds a block, but timing or
+  // reconnect can leave the two briefly divergent — take the larger
+  // of the two to stay consistent with the Miners table.
   const rows = $derived.by(() => {
     const ws = snap.data?.workers ?? [];
-    const enriched = ws.map((w) => ({
-      worker: w.worker,
-      bestRound: w.bestdiff,
-      bestEver: w.bestever || w.bestdiff,
-    }));
+    const cs = snap.data?.clients ?? [];
+    const clientByWorker = new Map<string, StratumClient>();
+    for (const c of cs) {
+      const wname = c.workername || `${c.address}.unnamed`;
+      clientByWorker.set(wname, c);
+    }
+    const enriched = ws.map((w) => {
+      const c = clientByWorker.get(w.worker);
+      const sessionBest = Math.max(c?.bestdiff ?? 0, w.bestdiff);
+      return {
+        worker: w.worker,
+        sessionBest,
+        bestEver: w.bestever || sessionBest,
+      };
+    });
     enriched.sort((a, b) => b.bestEver - a.bestEver);
     return enriched.slice(0, 10);
   });
@@ -28,7 +41,7 @@
         <tr>
           <th>#</th>
           <th>Worker</th>
-          <th class="num">Best (round)</th>
+          <th class="num">Best (session)</th>
           <th class="num">Best (ever)</th>
         </tr>
       </thead>
@@ -37,7 +50,7 @@
           <tr>
             <td>{i + 1}</td>
             <td class="mono">{r.worker}</td>
-            <td class="num">{formatDifficulty(r.bestRound)}</td>
+            <td class="num">{formatDifficulty(r.sessionBest)}</td>
             <td class="num">{formatDifficulty(r.bestEver)}</td>
           </tr>
         {/each}