browser: legacy CDP opt-in + gentle native-zap poll

Firefox no longer dials the dead ws://:9223/cdp bridge by default (it
error-looped); it's opt-in via globalThis.HANZO_LEGACY_CDP, matching
Chrome's native-ZAP-only default. And the ZAP native-host reconnect goes
3s -> 30s: with no MCP client there's no router, so hammering (and
re-launching the host) every 3s was pure noise — a live consumer is still
picked up within one interval. Pairs with zapd host connect-only.

packages/browser/src/background-firefox.ts

@@ -110,7 +110,11 @@ class HanzoFirefoxExtension {
 
   constructor() {
     console.log('[Hanzo] Firefox extension initializing...');
-    this.connect();
+    // Legacy ws://:9223 CDP bridge is OPT-IN (globalThis.HANZO_LEGACY_CDP). The
+    // default (and only) transport is the ZAP native host — see
+    // discoverZapServers() at EOF — matching Chrome. Without a bridge server the
+    // WS just error-looped, so it no longer runs unless explicitly enabled.
+    if ((globalThis as { HANZO_LEGACY_CDP?: boolean }).HANZO_LEGACY_CDP) this.connect();
   }
 
   private connect(): void {

packages/browser/src/shared/native-zap.ts

@@ -63,7 +63,11 @@ export interface NativeZapState {
 
 export type Dispatch = (method: string, params: any) => Promise<any> | any;
 
-const RECONNECT_MS = 3000;
+// Gentle safe poll: with no MCP client running there is no router to reach, so
+// the host connects-then-exits; probe every 30s instead of hammering (and
+// re-launching the native host) every 3s. A live consumer is picked up within
+// one interval.
+const RECONNECT_MS = 30_000;
 
 /** Connect to zapd via the native host, register as a browser provider, and
  *  dispatch inbound ROUTE commands to the browser. Self-heals on disconnect. */