feat(guild): translate <@user.name:NAME> -> <@userId>

Before persist/parse, resolve <@user.name:NAME> (outside backticks) via
Center and rewrite to <@userId>; unresolved tokens left as-is. Translated
ids then flow into the existing mention/wakeup/sub-frame logic.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/channels/mentions.ts

@@ -1,3 +1,58 @@
+// Split content into parts, tagging which are inside backtick spans so we
+// only touch mentions in non-code regions. Splitting keeps backtick runs.
+function codeAwareParts(content: string): { text: string; code: boolean }[] {
+  const raw = content.split(/(`+)/);
+  const parts: { text: string; code: boolean }[] = [];
+  let inCode = false;
+  for (const seg of raw) {
+    if (/^`+$/.test(seg)) {
+      parts.push({ text: seg, code: true });
+      inCode = !inCode;
+    } else {
+      parts.push({ text: seg, code: inCode });
+    }
+  }
+  return parts;
+}
+
+const NAME_MENTION_RE = /<@user\.name:([^>]+)>/g;
+
+// Names referenced via <@user.name:NAME> outside backtick spans.
+export function extractNameMentions(content: string): string[] {
+  if (typeof content !== 'string' || !content) return [];
+  const out: string[] = [];
+  const seen = new Set<string>();
+  for (const p of codeAwareParts(content)) {
+    if (p.code) continue;
+    let m: RegExpExecArray | null;
+    NAME_MENTION_RE.lastIndex = 0;
+    while ((m = NAME_MENTION_RE.exec(p.text)) !== null) {
+      const name = m[1].trim();
+      if (name && !seen.has(name)) {
+        seen.add(name);
+        out.push(name);
+      }
+    }
+  }
+  return out;
+}
+
+// Replace <@user.name:NAME> with <@userId> for resolved names (outside
+// backticks only); unresolved tokens are left untouched.
+export function replaceNameMentions(content: string, resolved: Record<string, string>): string {
+  if (typeof content !== 'string' || !content) return content;
+  return codeAwareParts(content)
+    .map((p) =>
+      p.code
+        ? p.text
+        : p.text.replace(NAME_MENTION_RE, (full, name: string) => {
+            const id = resolved[String(name).trim()];
+            return id ? `<@${id}>` : full;
+          }),
+    )
+    .join('');
+}
+
 // Parse <@user-id> mentions from message content. A mention does NOT count
 // when it sits inside a backtick span (single ` or triple ``` — any backtick
 // run toggles a code region). Returns unique ids in first-seen order.

src/common/center-auth.ts

@@ -25,3 +25,25 @@ export async function introspectGuildToken(token: string): Promise<{ active: boo
     user: data.user,
   };
 }
+
+// Resolve <@user.name:NAME> names to userIds within this guild node via
+// Center. Unresolved names are simply absent from the returned map.
+export async function resolveUserNames(names: string[]): Promise<Record<string, string>> {
+  const centerBaseUrl = process.env.FABRIC_BACKEND_GUILD_CENTER_BASE_URL;
+  const guildNodeId = process.env.FABRIC_BACKEND_GUILD_NODE_ID;
+  const centerApiKey = process.env.FABRIC_BACKEND_GUILD_CENTER_API_KEY;
+  if (!centerBaseUrl || !guildNodeId || !centerApiKey || !names.length) return {};
+
+  try {
+    const res = await fetch(`${centerBaseUrl}/api/auth/resolve-names`, {
+      method: 'POST',
+      headers: { 'content-type': 'application/json', 'x-api-key': centerApiKey },
+      body: JSON.stringify({ guildNodeId, names }),
+    });
+    if (!res.ok) return {};
+    const data = (await res.json()) as { resolved?: Record<string, string> };
+    return data.resolved ?? {};
+  } catch {
+    return {};
+  }
+}

src/messaging/messaging.controller.ts

@@ -18,7 +18,8 @@ import { Message } from '../entities/message.entity';
 import { IdempotencyRecord } from '../entities/idempotency-record.entity';
 import { WakeMapping } from '../entities/wake-mapping.entity';
 import { parseSlashCommand } from '../channels/slash-commands';
-import { parseMentions } from '../channels/mentions';
+import { parseMentions, extractNameMentions, replaceNameMentions } from '../channels/mentions';
+import { resolveUserNames } from '../common/center-auth';
 import { TurnService } from '../channels/turn.service';
 import { EventsService } from '../events/events.service';
 import { clampLimit, computeNextExpectedSeq } from './pagination.util';
@@ -146,8 +147,17 @@ export class MessagingController {
     const isRotating = xType === 'discuss' || xType === 'work';
     const authorUserId = String(body.authorUserId ?? 'anonymous');
 
+    // ---- translate <@user.name:NAME> -> <@userId> (outside backticks) via
+    // Center before anything else persists/parses the content
+    let content = body.content ?? '';
+    const names = extractNameMentions(content);
+    if (names.length) {
+      const map = await resolveUserNames(names);
+      content = replaceNameMentions(content, map);
+    }
+
     // ---- command interception: registered slash commands are never delivered
-    const cmd = parseSlashCommand(body.content ?? '');
+    const cmd = parseSlashCommand(content);
     if (cmd) {
       if (isRotating && cmd.name === 'no-reply') {
         const { ack } = await this.turn.onNoReply(channelId, authorUserId);
@@ -163,7 +173,7 @@ export class MessagingController {
     // ---- normal message
     const message = await this.persistMessage(channelId, {
       authorUserId,
-      content: body.content,
+      content,
       clientMessageId: body.clientMessageId,
       replyToMessageId: body.replyToMessageId,
       mentions: body.mentions,
@@ -180,8 +190,8 @@ export class MessagingController {
       data: responseBody,
     });
 
-    // mentions: <@id> outside backtick spans
+    // mentions: <@id> outside backtick spans (post name-translation)
-    const mentionIds = parseMentions(body.content ?? '');
+    const mentionIds = parseMentions(content);
 
     if (isRotating) {
       // discuss/work: rotation (incl. mention sub-frames) picks the target