feat(tabs): batch-close tabs by id list

Closing many tabs previously meant one IPC round-trip per tab
(tab.close() in a loop). Add a single batched path so callers can
close N tabs in one command, reusing the existing large-operation
throttle so the browser UI stays responsive.

- extension: tabs.close accepts tabIds: number[]; new branch feeds
  the array through processInBatches/chrome.tabs.remove
- sdk: tabs_close(tab_ids=...) takes tab IDs or Tab objects; the
  payload always carries "tabIds" (null when unused)
- tests: cover id-list and Tab-object batch close in test_api.py
- bump 0.10.3 -> 0.10.4 (pyproject.toml, manifest.json)

extension/manifest.json

@@ -1,7 +1,7 @@
 {
   "manifest_version": 3,
   "name": "browser-cli",
-  "version": "0.10.3",
+  "version": "0.10.4",
   "description": "Control your browser from the terminal or Python SDK",
   "permissions": [
     "tabs",