feat(cli): add opt-out anonymous telemetry via PostHog

Add anonymous usage telemetry to help improve the CLI. Uses PostHog's
HTTP batch API directly (zero new dependencies) with a 5-second timeout
and fail-silent behavior — telemetry never breaks the CLI.

What's collected: command names, render performance (duration, fps,
quality), template choices, OS/arch/Node version/CLI version.

What's NOT collected: file paths, project names, video content, or
any personally identifiable information.

Telemetry is:
- Disabled in dev mode (running via tsx)
- Disabled in CI (CI=true) or via HYPERFRAMES_NO_TELEMETRY=1
- Disabled when API key is placeholder (safe to merge before key is set)
- Controllable via `hyperframes telemetry [enable|disable|status]`
- Disclosed on first run with clear opt-out instructions

Config stored at ~/.hyperframes/config.json (0600 permissions).

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

packages/cli/src/telemetry/index.ts

@@ -0,0 +1,9 @@
+export { readConfig, writeConfig, incrementCommandCount, CONFIG_PATH } from "./config.js";
+export { trackEvent, flush, showTelemetryNotice } from "./client.js";
+export {
+  trackCommand,
+  trackRenderComplete,
+  trackRenderError,
+  trackInitTemplate,
+  trackBrowserInstall,
+} from "./events.js";