feat: harden remote serve and reuse connections

- Gate TCP serve commands with safe-by-default policies, per-key allow tokens, per-key rate limiting, and audit labels.
- Reuse authenticated encrypted remote sessions and parallelize/caches multi-browser fanout to reduce repeated handshake roundtrips.
- Increase paged native-host batch size with extension-side byte budgeting to speed large tab listings safely.
- Point install output at public Chrome Web Store / Firefox AMO listings by default, with --dev preserving unpacked workflows.
- Share search-engine metadata between CLI and SDK and bump the package/extension version to 0.16.0.
- Cover the new security, pooling, paging, install, and fanout behavior with expanded Python and extension tests.

browser_cli/native/host.py

@@ -7,7 +7,6 @@ It relays messages between extension (stdin/stdout Native Messaging protocol)
 and CLI (local IPC endpoint: Unix socket on Unix, named pipe on Windows).
 """
 import json
-import math
 import os
 import queue
 import socket
@@ -17,7 +16,7 @@ import uuid
 from pathlib import Path
 
 from browser_cli.native import local_server, protocol
-from browser_cli.constants import DEFAULT_ALIAS, DEFAULT_PAGE_SIZE, PAGEABLE_COMMANDS
+from browser_cli.constants import DEFAULT_ALIAS, DEFAULT_PAGE_SIZE, MAX_PAGED_ITEMS, PAGEABLE_COMMANDS
 from browser_cli.platform import endpoint_for_alias, is_windows, registry_path, runtime_dir
 from browser_cli.registry import update_registry
 
@@ -126,7 +125,10 @@ def _collect_paged_browser_command(cmd: dict) -> dict:
   offset = 0
   items = []
   total = None
-  max_pages = math.ceil(10_000 / PAGE_SIZE)
+  # Independent of PAGE_SIZE: the extension may return fewer items per page than
+  # requested (byte budget), so a page-count guard derived from PAGE_SIZE would
+  # falsely trip. Bound the page count by the absolute item cap instead.
+  max_pages = MAX_PAGED_ITEMS
   pages_fetched = 0
 
   while True:
@@ -154,7 +156,7 @@ def _collect_paged_browser_command(cmd: dict) -> dict:
     items.extend(page_items)
     total = data.get("total", total)
     next_offset = data.get("nextOffset")
-    if next_offset is None:
+    if next_offset is None or len(items) >= MAX_PAGED_ITEMS:
       break
     offset = int(next_offset)