feat: implement Call Center queues (mod_callcenter)

- Investigated the real callcenter_config command surface via
  'help callcenter_config' on the running FreeSWITCH before writing any
  code: queues only have load/unload/reload (static XML + reload, no
  'queue add' exists), while agents and tiers are fully dynamic via ESL
  commands (agent add, tier add) -- no file involved. This shapes the next
  phase (Agents/Tiers) differently from this one.
- queues table (tenant-scoped, RLS): strategy, moh/announce, wait times,
  tier rules, discard/abandoned handling, skip-agents-with-external-calls,
  recording_enabled
- packages/telephony: buildQueueXml()
- infrastructure/freeswitch: our own callcenter.conf.xml override (empties
  the vanilla static agents/tiers -- those become fully dynamic in the next
  phase) that includes callcenter_queues.conf.d/*.xml via X-PRE-PROCESS,
  same pattern as the Sofia gateway directory
- apps/api/src/queues: CRUD (POST/GET/GET:id/DELETE) using the queues.view/
  .manage permissions already in the seed
- b2bcall-fs-config (queue-sync.ts): one XML file per queue on a shared
  volume, synced via Redis pub/sub (b2bcall:queues:sync) on create/delete
  and once at boot -- same shape as trunk-sync.ts
- confirmed manually against the real FreeSWITCH, before coding the sync
  logic: 'queue load <name>' fails ('Invalid Queue not found!') for a file
  added after boot -- needs 'reloadxml' first to repopulate the in-memory
  XML tree from disk; after that, 'queue reload <name>' alone handles both
  create and update, no need to distinguish load vs reload
- verified end-to-end: created a queue (ROUND_ROBIN, maxWaitTime=120,
  discardAbandonedAfter=90), 'callcenter_config queue list' showed the
  correct values on the FreeSWITCH side; deleted it, list went back empty

docs/QUEUES.md

apps/api/src/queues/dto/create-queue.dto.ts

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+import { IsBoolean, IsIn, IsInt, IsOptional, IsString, Max, MaxLength, Min } from "class-validator";
+
+const STRATEGIES = [
+  "LONGEST_IDLE_AGENT",
+  "ROUND_ROBIN",
+  "TOP_DOWN",
+  "AGENT_WITH_LEAST_TALK_TIME",
+  "AGENT_WITH_FEWEST_CALLS",
+  "SEQUENTIALLY_BY_AGENT_ORDER",
+  "RING_ALL",
+  "RING_PROGRESSIVELY",
+] as const;
+
+export class CreateQueueDto {
+  @IsString()
+  @MaxLength(80)
+  name!: string;
+
+  @IsOptional()
+  @IsString()
+  @MaxLength(255)
+  description?: string;
+
+  @IsOptional()
+  @IsIn(STRATEGIES)
+  strategy?: (typeof STRATEGIES)[number];
+
+  @IsOptional()
+  @IsString()
+  @MaxLength(255)
+  mohSound?: string;
+
+  @IsOptional()
+  @IsString()
+  @MaxLength(255)
+  announceSound?: string;
+
+  @IsOptional()
+  @IsInt()
+  @Min(0)
+  @Max(3600)
+  announceFrequency?: number;
+
+  @IsOptional()
+  @IsInt()
+  @Min(0)
+  @Max(3600)
+  maxWaitTime?: number;
+
+  @IsOptional()
+  @IsInt()
+  @Min(0)
+  @Max(3600)
+  maxWaitTimeWithNoAgent?: number;
+
+  @IsOptional()
+  @IsString()
+  @MaxLength(80)
+  agentNoAnswerStatus?: string;
+
+  @IsOptional()
+  @IsBoolean()
+  tierRulesApply?: boolean;
+
+  @IsOptional()
+  @IsInt()
+  @Min(1)
+  @Max(3600)
+  tierRuleWaitSecond?: number;
+
+  @IsOptional()
+  @IsInt()
+  @Min(0)
+  @Max(3600)
+  discardAbandonedAfter?: number;
+
+  @IsOptional()
+  @IsBoolean()
+  abandonedResumeAllowed?: boolean;
+
+  @IsOptional()
+  @IsBoolean()
+  skipAgentsWithExternalCalls?: boolean;
+
+  @IsOptional()
+  @IsBoolean()
+  recordingEnabled?: boolean;
+}

apps/api/src/queues/queues.controller.ts

@@ -0,0 +1,125 @@
+import {
+  Body,
+  Controller,
+  Delete,
+  Get,
+  HttpCode,
+  HttpStatus,
+  NotFoundException,
+  Param,
+  Post,
+  UseGuards,
+} from "@nestjs/common";
+import { getPrismaClient, withTenantContext } from "@b2bcall/database";
+import { recordAuditEvent, type AccessTokenClaims } from "@b2bcall/auth";
+import { JwtAuthGuard } from "../common/guards/jwt-auth.guard";
+import { PermissionGuard } from "../common/guards/permission.guard";
+import { RequirePermission } from "../common/decorators/require-permission.decorator";
+import { CurrentUser } from "../common/decorators/current-user.decorator";
+import { getRedisClient } from "../common/redis";
+import { CreateQueueDto } from "./dto/create-queue.dto";
+
+const QUEUES_SYNC_CHANNEL = "b2bcall:queues:sync";
+
+async function notifyQueuesChanged(): Promise<void> {
+  await getRedisClient().publish(QUEUES_SYNC_CHANNEL, "sync");
+}
+
+@UseGuards(JwtAuthGuard, PermissionGuard)
+@Controller("queues")
+export class QueuesController {
+  @RequirePermission("queues.manage")
+  @Post()
+  async create(@CurrentUser() user: AccessTokenClaims, @Body() dto: CreateQueueDto) {
+    const prisma = getPrismaClient();
+    const tenantId = user.tenantId!;
+
+    const queue = await withTenantContext(prisma, tenantId, (tx) =>
+      tx.queue.create({
+        data: {
+          tenantId,
+          name: dto.name,
+          description: dto.description,
+          strategy: dto.strategy ?? "LONGEST_IDLE_AGENT",
+          mohSound: dto.mohSound,
+          announceSound: dto.announceSound,
+          announceFrequency: dto.announceFrequency ?? 0,
+          maxWaitTime: dto.maxWaitTime ?? 0,
+          maxWaitTimeWithNoAgent: dto.maxWaitTimeWithNoAgent ?? 0,
+          agentNoAnswerStatus: dto.agentNoAnswerStatus,
+          tierRulesApply: dto.tierRulesApply ?? false,
+          tierRuleWaitSecond: dto.tierRuleWaitSecond ?? 300,
+          discardAbandonedAfter: dto.discardAbandonedAfter ?? 60,
+          abandonedResumeAllowed: dto.abandonedResumeAllowed ?? false,
+          skipAgentsWithExternalCalls: dto.skipAgentsWithExternalCalls ?? true,
+          recordingEnabled: dto.recordingEnabled ?? false,
+        },
+      }),
+    );
+
+    await recordAuditEvent(prisma, {
+      action: "QUEUE_CREATE",
+      tenantId,
+      userId: user.sub,
+      entityType: "queue",
+      entityId: queue.id,
+      after: { name: queue.name, strategy: queue.strategy },
+    });
+
+    await notifyQueuesChanged();
+
+    return queue;
+  }
+
+  @RequirePermission("queues.view")
+  @Get()
+  async list(@CurrentUser() user: AccessTokenClaims) {
+    const prisma = getPrismaClient();
+    const tenantId = user.tenantId!;
+    return withTenantContext(prisma, tenantId, (tx) =>
+      tx.queue.findMany({ where: { deletedAt: null }, orderBy: { name: "asc" } }),
+    );
+  }
+
+  @RequirePermission("queues.view")
+  @Get(":id")
+  async get(@CurrentUser() user: AccessTokenClaims, @Param("id") id: string) {
+    const prisma = getPrismaClient();
+    const tenantId = user.tenantId!;
+    const queue = await withTenantContext(prisma, tenantId, (tx) =>
+      tx.queue.findFirst({ where: { id, deletedAt: null } }),
+    );
+    if (!queue) {
+      throw new NotFoundException();
+    }
+    return queue;
+  }
+
+  @RequirePermission("queues.manage")
+  @Delete(":id")
+  @HttpCode(HttpStatus.NO_CONTENT)
+  async remove(@CurrentUser() user: AccessTokenClaims, @Param("id") id: string) {
+    const prisma = getPrismaClient();
+    const tenantId = user.tenantId!;
+
+    const result = await withTenantContext(prisma, tenantId, (tx) =>
+      tx.queue.updateMany({
+        where: { id, deletedAt: null },
+        data: { deletedAt: new Date(), enabled: false },
+      }),
+    );
+    if (result.count === 0) {
+      throw new NotFoundException();
+    }
+
+    await recordAuditEvent(prisma, {
+      action: "QUEUE_DELETE",
+      tenantId,
+      userId: user.sub,
+      entityType: "queue",
+      entityId: id,
+    });
+
+    await notifyQueuesChanged();
+  }
+}

apps/api/src/queues/queues.module.ts

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+import { Module } from "@nestjs/common";
+import { QueuesController } from "./queues.controller";
+
+@Module({
+  controllers: [QueuesController],
+})
+export class QueuesModule {}