feat(cli): emit render_preflight_rejected telemetry for P1-3 pre-flight saves (#1856)

The P1-3 aspect/alpha/HDR pre-flight (#1843) aborts an incompatible render before any browser/ffmpeg work, but that "save" was invisible on dashboard 1783183 — indistinguishable from a deep failure or a user giving up.

checkRenderResolutionPreflight now returns { message, kind } (kind = the existing low-cardinality OutputResolutionIssueKind), and the render command emits render_preflight_rejected { kind } before exiting. No parsers change — the helper already carried kind. trackRenderPreflightRejected is typed to the union so the metric can't carry free text.

Tests: preflight tests assert kind for all five kinds; an events test locks the emit.

Further follow-up (still log-only): encoder-frame-0-exit counter and a P1-4 doctor cli_env_check event.

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

packages/cli/src/telemetry/events.test.ts

@@ -12,6 +12,7 @@ const {
   trackCommandFailure,
   trackCliError,
   trackRenderFeedback,
+  trackRenderPreflightRejected,
 } = await import("./events.js");
 
 describe("render telemetry events", () => {
@@ -39,6 +40,13 @@ describe("render telemetry events", () => {
     );
   });
 
+  it("emits render_preflight_rejected with the low-cardinality issue kind", () => {
+    trackRenderPreflightRejected({ kind: "aspect-mismatch" });
+    expect(trackEvent).toHaveBeenCalledWith("render_preflight_rejected", {
+      kind: "aspect-mismatch",
+    });
+  });
+
   it("forwards distinctId to trackEvent so studio renders attribute to the browser user", () => {
     trackRenderError({
       fps: 30,