chore: prepare verified CRX uploads and release 0.15.4

- Add helper scripts for Chrome Web Store verified CRX uploads using a dedicated RSA upload key protected by GPG.
- Document the verified upload packaging flow and ignore local signing secrets.
- Add npm packaging entry point for signed webstore CRX artifacts.
- Chunk large SDK tab close batches to avoid native-host response timeouts.
- Bump project and extension versions to 0.15.4 with matching tests.

browser_cli/sdk/tabs.py

@@ -6,6 +6,11 @@ from collections.abc import Callable, Iterable
 from browser_cli.models import BrowserCounts, Tab
 from browser_cli.sdk.base import Namespace
 
+# Keep SDK-driven bulk closes comfortably below the native-host response
+# timeout. The extension can close larger batches, but real browsers may take
+# much longer when hundreds of visible tabs are involved.
+BULK_CLOSE_CHUNK_SIZE = 50
+
 class TabsNS(Namespace):
   """List, open, close, move, and inspect browser tabs."""
 
@@ -75,6 +80,20 @@ class TabsNS(Namespace):
     ids = None
     if tab_ids is not None:
       ids = [t.id if isinstance(t, Tab) else t for t in tab_ids]
+    if ids is not None and len(ids) > BULK_CLOSE_CHUNK_SIZE and not inactive and not duplicates and tab_id is None:
+      closed = 0
+      for start in range(0, len(ids), BULK_CLOSE_CHUNK_SIZE):
+        chunk = ids[start:start + BULK_CLOSE_CHUNK_SIZE]
+        result = self.command("tabs.close", {
+          "tabId": None,
+          "tabIds": chunk,
+          "inactive": False,
+          "duplicates": False,
+          "gentleMode": gentle_mode,
+        })
+        closed += self.field(result, "closed", len(chunk))
+      return closed
+
     result = self.command("tabs.close", {
       "tabId": tab_id,
       "tabIds": ids,