Add uo-link WS ingest, storage tables and SSE broadcaster (phase 1)

The site now ingests the sidecar's live WebSocket feed and persists it to its
own MariaDB, and re-broadcasts curated events to browsers over SSE.

- schema: shard_events (append-only notable-kind log, sha1 dedupe_key +
  INSERT IGNORE for idempotent reconnect backfill), shard_online (current
  players, upsert/refresh/remove), shard_economy (gold-supply series),
  shard_houses (per-house decay stage + derived is_idoc).
- model/shardEvents + model/shardState: the .db.js/.model.js split; writes
  take camelCase event data, reads are shaped; online upsert uses COALESCE so
  a partial char.vitals refresh never blanks login fields.
- utils/shardIngest: single dispatcher routing each kind to state writes
  and/or the event log, then the broadcaster. High-frequency kinds
  (char.vitals, economy.supply) update state only. A changed server.hello
  bootId clears the stale online roster. Deps are injected for unit testing.
- utils/uoLinkSocket: the server's first outbound WS client (ws dep). Verifies
  the ws.hello protocol, backfills via /history + /economy on every
  (re)connect (dedupe handles overlap), reconnects with capped backoff, and
  mirrors connection state into uo_link_config. Self-guards: only connects when
  the integration is enabled with a token.
- utils/shardBroadcast: SSE fan-out with public (safe kinds only) and admin
  (all) channels, keepalive pings, per-client cleanup.
- server.js: start the ingest socket on boot (no-op until configured) and stop
  it + close SSE streams on graceful shutdown.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011qPmpmVH1xGCiZoz9m9vW3

server/src/model/shardEvents/shardEvents.db.js

@@ -0,0 +1,31 @@
+const { query } = require('../../utils/db')
+
+// INSERT IGNORE on the UNIQUE dedupe_key — a re-ingested event (WS-reconnect
+// backfill overlap) is silently skipped rather than duplicated. Returns true if
+// a new row was actually inserted.
+async function insertIgnore({ kind, t, bootId, payload, dedupeKey }) {
+  const res = await query(
+    `INSERT IGNORE INTO shard_events (kind, t, boot_id, payload, dedupe_key)
+     VALUES (?, ?, ?, ?, ?)`,
+    [kind, t, bootId || null, JSON.stringify(payload), dedupeKey],
+  )
+  return res.affectedRows > 0
+}
+
+// Recent events, newest first. Optional kind filter; limit is clamped by the model.
+async function list({ kind, limit }) {
+  if (kind) {
+    return query(
+      `SELECT id, kind, t, boot_id, payload, created_at
+         FROM shard_events WHERE kind = ? ORDER BY t DESC LIMIT ?`,
+      [kind, limit],
+    )
+  }
+  return query(
+    `SELECT id, kind, t, boot_id, payload, created_at
+       FROM shard_events ORDER BY t DESC LIMIT ?`,
+    [limit],
+  )
+}
+
+module.exports = { insertIgnore, list }