feat: implement app-side telemetry sender

Add the shared telemetry sender, wire the CLI/server emit points,
and cover the config and completion behavior with tests.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

packages/shared/src/telemetry/index.ts

@@ -0,0 +1,17 @@
+export { TelemetryClient } from "./client.js";
+export { resolveTelemetryConfig } from "./config.js";
+export { loadOrCreateState } from "./state.js";
+export {
+  trackInstallStarted,
+  trackInstallCompleted,
+  trackCompanyImported,
+  trackAgentFirstHeartbeat,
+  trackAgentTaskCompleted,
+  trackErrorHandlerCrash,
+} from "./events.js";
+export type {
+  TelemetryConfig,
+  TelemetryState,
+  TelemetryEventEnvelope,
+  TelemetryEventName,
+} from "./types.js";