perf(memory): release old navigation request in NetworkCollector (#1200)

Issue #1192

## Problem
In `--autoConnect` mode, `chrome-devtools-mcp` experiences a severe
memory leak (~13 MB/min) when Chrome is actively used. This eventually
leads to OOM crashes or kernel panics.

The root cause is in `src/PageCollector.ts`:
1. `NetworkCollector` overrides `splitAfterNavigation` but forgets to
call `navigations.splice(this.#maxNavigationSaved)`, causing the array
of navigations to grow infinitely.
2. Even within a single navigation (e.g., in long-lived SPA
applications), the `navigations[0]` array grows infinitely because there
is no limit on the number of items collected per navigation. Since
`HTTPRequest` objects are heavy, this quickly exhausts memory.

## Solution
1. Changed `#maxNavigationSaved` to `protected maxNavigationSaved` so
subclasses can access it.
2. Added `navigations.splice(this.maxNavigationSaved)` to
`NetworkCollector.splitAfterNavigation` to ensure old navigations are
properly discarded.
3. Introduced `protected maxItemsPerNavigation = 5000` to limit the
number of items stored per navigation. When the limit is reached, the
oldest item is removed (`shift()`), preventing unbounded memory growth
in SPAs.

Tested locally by running `npm run build` and verifying the fix.

---------

Co-authored-by: Wolfgang Beyer <woolfi.b@gmail.com>

Author: flobo3

src/PageCollector.ts

@@ -62,7 +62,7 @@ export class PageCollector<T> {
     collector: (item: T) => void,
   ) => ListenerMap<PageEvents>;
   #listeners = new WeakMap<Page, ListenerMap>();
-  #maxNavigationSaved = 3;
+  protected maxNavigationSaved = 3;
 
   /**
    * This maps a Page to a list of navigations with a sub-list
@@ -159,7 +159,7 @@ export class PageCollector<T> {
     }
     // Add the latest navigation first
     navigations.unshift([]);
-    navigations.splice(this.#maxNavigationSaved);
+    navigations.splice(this.maxNavigationSaved);
   }
 
   protected cleanupPageDestroyed(page: Page) {
@@ -183,7 +183,7 @@ export class PageCollector<T> {
     }
 
     const data: T[] = [];
-    for (let index = this.#maxNavigationSaved; index >= 0; index--) {
+    for (let index = this.maxNavigationSaved; index >= 0; index--) {
       if (navigations[index]) {
         data.push(...navigations[index]);
       }
@@ -409,5 +409,6 @@ export class NetworkCollector extends PageCollector<HTTPRequest> {
     } else {
       navigations.unshift([]);
     }
+    navigations.splice(this.maxNavigationSaved);
   }
 }

tests/PageCollector.test.ts

@@ -284,6 +284,29 @@ describe('NetworkCollector', () => {
     page.emit('request', request);
     assert.equal(collector.getData(page, true).length, 3);
   });
+
+  it('should not grow beyond maxNavigationSaved', async () => {
+    const browser = getMockBrowser();
+    const page = (await browser.pages())[0];
+    const mainFrame = page.mainFrame();
+    const collector = new NetworkCollector(browser);
+    await collector.init([page]);
+
+    // Simulate 5 navigations (maxNavigationSaved is 3)
+    for (let i = 0; i < 5; i++) {
+      const req = getMockRequest({
+        url: `http://example.com/nav${i}`,
+        navigationRequest: true,
+        frame: mainFrame,
+      });
+      page.emit('request', req);
+      page.emit('framenavigated', mainFrame);
+    }
+
+    // We expect 3 arrays in navigations (current + 2 saved)
+    // Each navigation has 1 request, so total should be 3
+    assert.equal(collector.getData(page, true).length, 3);
+  });
 });
 
 describe('ConsoleCollector', () => {