fix: capture server nickname (member displayName) per action

Rename server_name (guild name) to server_nick and populate it from
the member's server-specific display name (metadata.member.displayName)
at write time. This is what the moderation dashboard should show as
TARGET — e.g. server nick 'Bandar Togel「✔ ᵛᵉʳᶦᶠᶦᵉᵈ 」' for global
username '.nichiyobi'. Backfilled 210 existing actions from messages
metadata (reset_nickname rows now show 'Sarjana .jav', 'Penindas
Minoritas', etc). Frontend TARGET shows server nick with global
username as secondary context.

services/discord-gateway/drizzle/migrations/0019_rename_server_name_to_server_nick.sql

@@ -0,0 +1,4 @@
+-- Rename server_name (guild name) -> server_nick (member's server nickname)
+-- server_name was added in 0018 but never populated (all NULL), so renaming
+-- the empty column is safe and keeps retention semantics correct.
+ALTER TABLE "moderation_actions" RENAME COLUMN "server_name" TO "server_nick";

services/discord-gateway/drizzle/migrations/meta/_journal.json

@@ -134,6 +134,13 @@
       "when": 1787820000000,
       "tag": "0018_add_server_name_to_moderation_actions",
       "breakpoints": true
+    },
+    {
+      "idx": 19,
+      "version": "7",
+      "when": 1787830000000,
+      "tag": "0019_rename_server_name_to_server_nick",
+      "breakpoints": true
     }
   ]
 }

services/discord-gateway/src/modules/ai-moderation/autoDeleteManager.ts

@@ -2,6 +2,7 @@ import type { Client, PermissionString } from "discord.js-selfbot-v13";
 import { LRUCache } from "lru-cache";
 import { createChildLogger } from "@/shared/logger/index";
 import { config } from "../../shared/config/config.js";
+import { parseRichMessageMetadata } from "../message-capture/messageMetadata.js";
 import { messageStore } from "../message-capture/messageStore.js";
 import type { MessageRecord } from "../message-capture/types.js";
 import {
@@ -269,10 +270,24 @@ function hasPermissionApi(channel: unknown): channel is {
 
 // ─── Database Action Log ─────────────────────────────────────────────
 
+/**
+ * Extract the member's server-specific display name (nickname) from a
+ * captured message's metadata. Falls back to the global username when no
+ * server nickname exists (member.displayName defaults to the guild nickname
+ * when set, otherwise the global username).
+ */
+function resolveServerNick(message: MessageRecord): string | null {
+  try {
+    const parsed = parseRichMessageMetadata(message.metadata);
+    return parsed?.member?.displayName ?? message.username ?? null;
+  } catch {
+    return message.username ?? null;
+  }
+}
+
 async function logAutoDeleteAttempt(
   message: MessageRecord,
   result: AutoDeleteResult,
-  serverName?: string | null,
 ): Promise<void> {
   try {
     await messageStore.createModerationAction({
@@ -283,7 +298,7 @@ async function logAutoDeleteAttempt(
       reason: result.reason,
       ...verdictToActionFields(message),
       username: message.username,
-      server_name: serverName ?? null,
+      server_nick: resolveServerNick(message),
       executed_by: "auto-delete-manager",
       status: result.deleted
         ? "executed"
@@ -350,7 +365,7 @@ export async function attemptAutoDeleteFlaggedMessage(
               "nickname melanggar aturan server (offensive_username); pesan dibiarkan",
             ...verdictToActionFields(message),
             username: message.username,
-            server_name: null,
+            server_nick: resolveServerNick(message),
             executed_by: "auto-delete-manager",
             status: resetOk ? "executed" : "failed",
             error: resetOk ? null : "nickname_reset_failed",
@@ -471,7 +486,7 @@ export async function attemptAutoDeleteFlaggedMessage(
         skipped: true,
         reason: "dry_run",
       };
-      await logAutoDeleteAttempt(message, result, guild.name);
+      await logAutoDeleteAttempt(message, result);
       logger.info(
         { messageId: message.id, channelId },
         "Auto-delete dry-run: would delete flagged message",
@@ -503,7 +518,7 @@ export async function attemptAutoDeleteFlaggedMessage(
       skipped: false,
       reason: "deleted",
     };
-    await logAutoDeleteAttempt(message, result, guild.name);
+    await logAutoDeleteAttempt(message, result);
     logger.info(
       { messageId: message.id, channelId },
       "Auto-deleted AI-flagged message",

services/discord-gateway/src/modules/command-handler/moderation.handler.ts

@@ -104,7 +104,7 @@ export class ModerationHandler {
           | "ban_user",
         reason: payload.reason ?? null,
         username: null,
-        server_name: null,
+        server_nick: null,
         executed_by: payload.executed_by ?? "command-handler",
         status: "executed",
         error: null,

services/discord-gateway/src/shared/database/schema.ts

@@ -643,7 +643,7 @@ export const pgModerationActionsTable = pgTable(
     evidence: pgText("evidence"), // JSON array of short quoted snippets
     policy_version: pgText("policy_version"), // rules.ts policy version string
     username: pgText("username"), // denormalized from messages table for retention safety
-    server_name: pgText("server_name"), // denormalized guild name for retention safety
+    server_nick: pgText("server_nick"), // member's server-specific display name (nickname), from metadata.member.displayName
   },
   (table) => ({
     messageIdIdx: pgIndex("idx_moderation_actions_message_id").on(

services/discord-gateway/src/shared/database/schema/messages.ts

@@ -60,7 +60,7 @@ export const pgModerationActionsTable = pgTable(
     evidence: pgText("evidence"), // JSON array of short quoted snippets
     policy_version: pgText("policy_version"), // rules.ts policy version string
     username: pgText("username"), // denormalized from messages table for retention safety
-    server_name: pgText("server_name"), // denormalized guild name for retention safety
+    server_nick: pgText("server_nick"), // member's server-specific display name (nickname), from metadata.member.displayName
   },
   (table) => ({
     messageIdIdx: pgIndex("idx_moderation_actions_message_id").on(

services/discord-gateway/src/shared/moderation-types.ts

@@ -209,7 +209,7 @@ export interface ModerationAction {
   action_type: ModerationActionType;
   reason: string | null;
   username: string | null;
-  server_name: string | null;
+  server_nick: string | null;
   executed_by: string | null;
   status: "pending" | "executed" | "failed";
   error: string | null;