feat: recording analysis module with Deepgram + AI insights + Redis cache

- RecordingsModule: POST /api/recordings/analyze
- Deepgram pre-recorded API: diarize, summarize, topics, sentiment, utterances
- AI insights via OpenAI generateObject: call outcome, coaching, compliance, satisfaction
- Redis cache: 7-day TTL per callId, check before hitting Deepgram/OpenAI
- Generic getCache/setCache added to SessionService for cross-module use

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

src/recordings/recordings.controller.ts

@@ -0,0 +1,53 @@
+import { Controller, Post, Body, Logger, HttpException } from '@nestjs/common';
+import { RecordingsService } from './recordings.service';
+import { SessionService } from '../auth/session.service';
+
+const CACHE_TTL = 7 * 24 * 3600; // 7 days
+
+@Controller('api/recordings')
+export class RecordingsController {
+    private readonly logger = new Logger(RecordingsController.name);
+
+    constructor(
+        private readonly recordings: RecordingsService,
+        private readonly session: SessionService,
+    ) {}
+
+    @Post('analyze')
+    async analyze(@Body() body: { recordingUrl: string; callId?: string }) {
+        if (!body.recordingUrl) {
+            throw new HttpException('recordingUrl required', 400);
+        }
+
+        const cacheKey = body.callId ? `call:analysis:${body.callId}` : null;
+
+        // Check Redis cache first
+        if (cacheKey) {
+            try {
+                const cached = await this.session.getCache(cacheKey);
+                if (cached) {
+                    this.logger.log(`[RECORDING] Cache hit: ${cacheKey}`);
+                    return JSON.parse(cached);
+                }
+            } catch {}
+        }
+
+        this.logger.log(`[RECORDING] Cache miss — analyzing: ${body.recordingUrl} callId=${body.callId ?? 'none'}`);
+
+        try {
+            const analysis = await this.recordings.analyzeRecording(body.recordingUrl);
+            this.logger.log(`[RECORDING] Analysis complete: ${analysis.transcript.length} utterances, sentiment=${analysis.sentiment}`);
+
+            // Cache the result
+            if (cacheKey) {
+                this.session.setCache(cacheKey, JSON.stringify(analysis), CACHE_TTL)
+                    .catch(err => this.logger.warn(`[RECORDING] Cache write failed: ${err}`));
+            }
+
+            return analysis;
+        } catch (error: any) {
+            this.logger.error(`[RECORDING] Analysis failed: ${error.message}`);
+            throw new HttpException(error.message ?? 'Analysis failed', 502);
+        }
+    }
+}