fix: disposition for answered inbound calls + SLA timing wiring + backfill

Three related fixes:

1. Disposition for answered inbound calls
   Previously the dispose endpoint sent the agent's choice to Ozonetel
   but never wrote it back to the platform Call record. The webhook's
   pre-disposition value ("General Enquiry" → INFO_PROVIDED) persisted.
   Now: dispose endpoint finds the Call by UCID and updates disposition
   to the agent's actual selection.

2. SLA timing wiring (assignedAt / answeredAt / responseTimeS)
   patchCallTiming() existed but was never called. Now wired into
   handleCallEvent:
   - "Calling" event → writes assignedAt (ring start)
   - "Answered" event → writes answeredAt + computes responseTimeS
     (answeredAt - startedAt = caller wait time)
   Uses patchCallTimingByUcid helper that looks up Call by UCID.

3. Backfill maint endpoint: POST /api/maint/backfill-call-disposition-timing
   Walks calls for a given date, joins to CDR by UCID (both legs),
   patches disposition (from CDR's mapped value, always overwrites),
   timing fields (answeredAt, assignedAt, responseTimeS from CDR),
   and CDR-specific durations (handlingTimeS, acwDurationS, holdDurationS).
   Idempotent — safe to run multiple times.

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

src/ozonetel/ozonetel-agent.controller.ts

@@ -278,6 +278,34 @@ export class OzonetelAgentController {
             }
         }
 
+        // Update disposition on answered inbound calls. The webhook creates
+        // the Call record with the Ozonetel default disposition ("General
+        // Enquiry" → INFO_PROVIDED) before the agent disposes. Now that the
+        // agent has submitted their actual disposition, write it back to the
+        // platform Call record by matching on UCID.
+        //
+        // Skipped for outbound (already created with correct disposition
+        // above) and for missed-call callbacks (handled in the block above).
+        if (!body.missedCallId && body.direction !== 'OUTBOUND' && body.ucid) {
+            try {
+                const callData = await this.platform.query<any>(
+                    `{ calls(first: 1, filter: { ucid: { eq: "${body.ucid}" } }) { edges { node { id } } } }`,
+                );
+                const callId = callData?.calls?.edges?.[0]?.node?.id;
+                if (callId) {
+                    await this.platform.query<any>(
+                        `mutation($id: UUID!, $data: CallUpdateInput!) { updateCall(id: $id, data: $data) { id } }`,
+                        { id: callId, data: { disposition: body.disposition } },
+                    );
+                    this.logger.log(`[DISPOSE] Updated inbound call ${callId} disposition → ${body.disposition}`);
+                } else {
+                    this.logger.warn(`[DISPOSE] No Call found for ucid=${body.ucid} — disposition not persisted`);
+                }
+            } catch (err: any) {
+                this.logger.warn(`[DISPOSE] Failed to update inbound call disposition: ${err.message}`);
+            }
+        }
+
         // Auto-assign next missed call to this agent
         try {
             await this.missedQueue.assignNext(agentId);