feat(app): export isDev platform flag and enable runtime metrics in dev

Adds a shared isDev constant alongside isWeb/isNative and wires daemon
clients to collect runtime metrics (10s interval) only in development.

packages/app/src/constants/platform.ts

@@ -10,6 +10,7 @@ import { isElectronRuntime, isElectronRuntimeMac } from "@/desktop/host";
 // Default is cross-platform. Gate only when you must:
 //   isWeb      → DOM APIs (document, window, <div>, addEventListener)
 //   isNative   → Native-only APIs (Haptics, StatusBar, push tokens, camera)
+//   isDev      → Development-only diagnostics and instrumentation
 //   isElectron → Desktop wrapper features (file dialogs, titlebar, updates)
 //
 // For layout decisions, use useIsCompactFormFactor() from constants/layout.ts.
@@ -22,6 +23,9 @@ export const isWeb = Platform.OS === "web";
 /** iOS or Android — the JS runtime is React Native. */
 export const isNative = Platform.OS !== "web";
 
+/** Development build/runtime — true in Metro dev bundles, false in production. */
+export const isDev = Boolean((globalThis as { __DEV__?: boolean }).__DEV__);
+
 // ---------------------------------------------------------------------------
 // Electron detection (cached — only caches `true`, keeps checking if false
 // because the desktop bridge may load after initial module evaluation)

packages/app/src/runtime/host-runtime.ts

@@ -30,6 +30,7 @@ import {
   buildLocalDaemonTransportUrl,
   createDesktopLocalDaemonTransportFactory,
 } from "@/desktop/daemon/desktop-daemon-transport";
+import { isDev } from "@/constants/platform";
 import { applyFetchedAgentDirectory } from "@/utils/agent-directory-sync";
 import { useSessionStore, type Agent } from "@/stores/session-store";
 
@@ -433,6 +434,7 @@ function createDefaultDeps(): HostRuntimeControllerDeps {
         clientType: "mobile" as const,
         appVersion: resolveAppVersion() ?? undefined,
         runtimeGeneration,
+        ...(isDev ? { runtimeMetricsIntervalMs: 10_000 } : {}),
       };
       if (connection.type === "directSocket" || connection.type === "directPipe") {
         return new DaemonClient({

packages/app/src/utils/scroll-jank-investigation.ts

@@ -1,4 +1,4 @@
-import { isWeb } from "@/constants/platform";
+import { isDev, isWeb } from "@/constants/platform";
 
 type ListenerStats = {
   adds: number;
@@ -91,7 +91,6 @@ const SOURCE_LABEL = "[ScrollJankInvestigation]";
 
 function shouldInstall(): boolean {
   const runtime = globalThis as ScrollInvestigationGlobal;
-  const isDev = Boolean((globalThis as { __DEV__?: boolean }).__DEV__);
   return isWeb && isDev && !runtime.__PASEO_SCROLL_JANK_INVESTIGATION_DISABLED__;
 }
 

packages/app/src/utils/test-daemon-connection.ts

@@ -8,6 +8,7 @@ import {
   buildLocalDaemonTransportUrl,
   createDesktopLocalDaemonTransportFactory,
 } from "@/desktop/daemon/desktop-daemon-transport";
+import { isDev } from "@/constants/platform";
 
 function normalizeNonEmptyString(value: unknown): string | null {
   if (typeof value !== "string") return null;
@@ -57,6 +58,7 @@ export async function buildClientConfig(
     appVersion: resolveAppVersion() ?? undefined,
     suppressSendErrors: true,
     reconnect: { enabled: false },
+    ...(isDev ? { runtimeMetricsIntervalMs: 10_000 } : {}),
     ...(connection.type === "directSocket" || connection.type === "directPipe"
       ? localTransportFactory
         ? { transportFactory: localTransportFactory }