refactor: reorganize client transport and extension internals

- Split client, native, remote, serve, markdown, and SDK internals into focused packages with direct imports.
- Move local and remote transport framing/protocol helpers behind clearer module boundaries.
- Break up the extension injected DOM logic into a separate content dispatch bundle and dedicated content modules.
- Add explicit client handling for passive remote discovery without noisy PQ warnings.
- Keep behavior covered with updated unit, integration, and extension tests.

extension/src/core/throttle.ts

@@ -9,6 +9,11 @@ export const LARGE_OPERATION_BATCH_SIZE = 25;
 export const LARGE_OPERATION_PAUSE_MS = 25;
 export const GENTLE_OPERATION_BATCH_SIZE = 8;
 export const GENTLE_OPERATION_PAUSE_MS = 100;
+const DEBUG_LARGE_OPERATIONS = false;
+
+function debugLargeOperation(message: string) {
+  if (DEBUG_LARGE_OPERATIONS) console.log(message);
+}
 
 export async function hasAudibleTabs() {
   const audibleTabs = await chrome.tabs.query({ audible: true });
@@ -19,11 +24,11 @@ let largeOperationQueue: Promise<void> = Promise.resolve();
 
 export async function runLargeOperation<T>(name: string, fn: () => Promise<T>): Promise<T> {
   const run = largeOperationQueue.then(async () => {
-    console.log(`[browser-cli] large operation start: ${name}`);
+    debugLargeOperation(`[browser-cli] large operation start: ${name}`);
     try {
       return await fn();
     } finally {
-      console.log(`[browser-cli] large operation done: ${name}`);
+      debugLargeOperation(`[browser-cli] large operation done: ${name}`);
     }
   });
   largeOperationQueue = run.then(() => {}, () => {});