perf(coding-agent): deferred heavy module imports to startup paths

- Lazy-loaded OTEL SDK, HTML export, TTSR, and autoresearch modules.
- Made resolveMemoryBackend async to import backends on demand.
- Replaced backend resolution with direct settings reads for rekey checks.

packages/coding-agent/test/otel-export-probe.ts

@@ -35,7 +35,7 @@ const server = Bun.serve({
 process.env.OTEL_EXPORTER_OTLP_TRACES_ENDPOINT = `http://localhost:${server.port}/v1/traces`;
 process.env.OTEL_SERVICE_NAME = "oh-my-pi-export-probe";
 
-initTelemetryExport();
+await initTelemetryExport();
 if (!isTelemetryExportEnabled()) {
 	console.error("PROBE: provider did not register");
 	await server.stop(true);