feat(telemetry): track TTY vs non-TTY invocations via metric

Emits a `cli.invocation` counter metric with an `is_tty` attribute on
every CLI call. This lets us measure what percentage of usage comes from
agents and CI vs interactive terminals in the Sentry Metrics dashboard.

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

Author: betegon

src/lib/telemetry.ts

@@ -342,6 +342,11 @@ export function initSentry(enabled: boolean): Sentry.BunClient | undefined {
     // Tag whether targeting self-hosted Sentry (not SaaS)
     Sentry.setTag("is_self_hosted", !isSentrySaasUrl(getSentryBaseUrl()));
 
+    // Track TTY vs non-TTY invocations to measure agent/CI usage percentage
+    Sentry.metrics.count("cli.invocation", 1, {
+      attributes: { is_tty: !!process.stdout.isTTY },
+    });
+
     // Wire up consola → Sentry log forwarding now that the client is active
     attachSentryReporter();