feat(calls): consolidate agent identity via Ozonetel CDR

Ozonetel's webhook AgentName is a transfer-chain display string — same
display can collide (two agents both named "GlobalHealthX" with distinct
agent IDs), and chained like "RamaiahAdmin -> Ganesh Bandi -> GlobalHealthX".
Team Performance was bucketing every unique raw string as a separate
"agent", producing 7 rows for 3 real agents.

Fix — authoritative agent link via CDR AgentID (unique):

- New AgentLookupService (platform module): case-insensitive
  ozonetelAgentId → Agent UUID cache, shared across webhook / dispose /
  enrichment / backfill paths
- Webhook + outbound-dispose now persist UCID on Call so CDR can join
- Outbound dispose resolves agent relation at create time and overwrites
  from CDR AgentID post-hoc (catches dial transfers)
- New CdrEnrichmentService: every 30 min fetches today + yesterday CDR,
  patches Calls missing agentId / transferredTo / transferType by UCID
  join. Well under Ozonetel's 2 req/min cap.
- Historical backfill maint endpoint: /api/maint/enrich-call-agents
  with configurable day window (default 2, max 15). Rate-limited at 35s
  between dates.

Call schema additions (synced on Global + Ramaiah): agent relation,
ucid, transferredTo, transferType. agentName remains for legacy/display.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/platform/platform.module.ts

@@ -1,8 +1,9 @@
 import { Module } from '@nestjs/common';
 import { PlatformGraphqlService } from './platform-graphql.service';
+import { AgentLookupService } from './agent-lookup.service';
 
 @Module({
-    providers: [PlatformGraphqlService],
-    exports: [PlatformGraphqlService],
+    providers: [PlatformGraphqlService, AgentLookupService],
+    exports: [PlatformGraphqlService, AgentLookupService],
 })
 export class PlatformModule {}