feat(shard): Protocol 2.0 boards UI — guilds, governors, houses, players-online

Phase 2: the public UI for the four new boards, following the ChampSpawns live
pattern (snapshot via useAsync + merge SSE deltas with useShardFeed).

- Players Online widget (components/PlayersOnline.jsx): total + region breakdown
  rolled up into display buckets (data/regionBuckets.js — the one place to retune
  the grouping); live via presence.online. Placed on the Shard page, replacing the
  static players-online stat tile.
- Guilds (/site/guilds): searchable board of rosters/alliances/leaders with a
  "recently joined" strip from guild.join.
- Governors (/site/governors): one card per city with a placeholder crest
  (data/cityCrests.js — swap for real art without touching components), election
  phase badge + autoPickAt countdown, and an on-demand "past governors" term
  history (the look-back reads the ledger captured in Phase 1). Clean empty state
  when City Loyalty isn't enabled.
- Houses (/site/houses): searchable registry with decay badges; price labelled
  "placement value", not a for-sale flag.
- API client methods + nav links (Guilds / Governors / Houses).

Client build clean (240 modules).

Refs .plans/protocol2-integration.md (Phase 2).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client/src/components/PlayersOnline.jsx

@@ -0,0 +1,84 @@
+import { useMemo } from 'react'
+import { useAsync } from '../lib/useAsync.js'
+import { useShardFeed } from '../lib/useShardFeed.js'
+import { bucketize } from '../data/regionBuckets.js'
+import { api } from '../api/client.js'
+
+// Compact live "Players Online" widget. Loads the presence.online aggregate once,
+// then keeps the total + region breakdown current from the presence.online SSE
+// kind. The raw byRegion map is rolled up into display buckets (see
+// data/regionBuckets.js). NOT a page — drop it into any panel/column.
+const PRESENCE_KINDS = new Set(['presence.online'])
+
+export default function PlayersOnline() {
+  const { loading, error, data } = useAsync(() => api.shard.presence())
+  const { events } = useShardFeed({ filter: PRESENCE_KINDS, max: 4 })
+
+  // The freshest snapshot wins: the newest buffered presence.online event, else
+  // the initial fetch.
+  const snapshot = events[0] || data
+
+  const { total, rows } = useMemo(() => {
+    const count = Number(snapshot?.count) || 0
+    const { rows: bucketRows } = bucketize(snapshot?.byRegion)
+    return { total: count, rows: bucketRows }
+  }, [snapshot])
+
+  return (
+    <section className="panel" style={{ padding: 20 }}>
+      <div
+        className="sans"
+        style={{ display: 'flex', alignItems: 'baseline', justifyContent: 'space-between', gap: 12 }}
+      >
+        <span
+          style={{
+            color: 'var(--accent)',
+            fontSize: '0.7rem',
+            letterSpacing: '0.12em',
+            textTransform: 'uppercase',
+          }}
+        >
+          Players online
+        </span>
+        <span className="display" style={{ fontSize: '1.5rem', color: 'var(--head)', lineHeight: 1 }}>
+          {loading ? '—' : total}
+        </span>
+      </div>
+
+      {error && (
+        <p className="sans dim" style={{ margin: '12px 0 0', fontSize: '0.84rem' }}>
+          Population is unavailable right now.
+        </p>
+      )}
+
+      {!loading && !error && (
+        <div style={{ marginTop: 14, display: 'flex', flexDirection: 'column', gap: 6 }}>
+          {rows.length === 0 ? (
+            <p className="sans dim" style={{ margin: 0, fontSize: '0.84rem' }}>
+              {total > 0 ? 'Locations are settling…' : 'The realm is quiet.'}
+            </p>
+          ) : (
+            rows.map((r) => (
+              <div
+                key={r.id}
+                className="sans"
+                style={{
+                  display: 'flex',
+                  alignItems: 'center',
+                  justifyContent: 'space-between',
+                  gap: 12,
+                  fontSize: '0.9rem',
+                  color: 'var(--ink)',
+                }}
+              >
+                <span>{r.label}</span>
+                {/* tabular figures keep the right-aligned counts in a clean column */}
+                <span className="dim" style={{ fontVariantNumeric: 'tabular-nums' }}>{r.count}</span>
+              </div>
+            ))
+          )}
+        </div>
+      )}
+    </section>
+  )
+}