feat(producer,cli): render-reliability telemetry counters for capture hardening (#1850)

Follow-up to the render-reliability batch (#1841/#1842/#1843). Threads two capture-reliability counters through the existing observability → CLI-telemetry pipeline (no new PostHog wiring) so #1842's hardening is measurable on dashboard 1783183:

- transient-retry burn (CaptureAttemptSummary.reason gains "transient-retry"; counted into RenderCaptureObservability.transientRetries on BOTH the recovered and the still-failed paths via a shared helper).
- OOM classification (memoryExhaustionDetected set when describeMemoryExhaustion classifies the failure).

Surfaced as capture_transient_retries + capture_memory_exhaustion_detected render-event props. Tests cover the attempt tagging and the payload mapping.

Further follow-up (different subsystems): encoder-frame-0-exit signal, and P1-3 pre-flight-rejection / P1-4 cli_env_check counters.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/producer/src/services/render/observability.ts

@@ -43,6 +43,15 @@ export interface RenderCaptureObservability {
   protocolTimeoutMs?: number;
   pageNavigationTimeoutMs?: number;
   playerReadyTimeoutMs?: number;
+  /**
+   * Render-reliability counters (see PostHog dashboard 1783183). Emitted so the
+   * capture-hardening in #1842 is measurable from a metric, not just logs:
+   * how often the bounded transient-tab-death retry fired on a render that
+   * ultimately succeeded, and whether the failure was classified as an
+   * out-of-memory exhaustion (`Set maximum size exceeded` and friends).
+   */
+  transientRetries?: number;
+  memoryExhaustionDetected?: boolean;
 }
 
 export interface RenderExtractionObservability {