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/search/engines.py

@@ -0,0 +1,53 @@
+"""Shared search-engine metadata for SDK and CLI search commands."""
+from __future__ import annotations
+
+ENGINES = {
+  "google":        "https://www.google.com/search?q={query}",
+  "brave":         "https://search.brave.com/search?q={query}",
+  "duckduckgo":    "https://duckduckgo.com/?q={query}",
+  "ddg":           "https://duckduckgo.com/?q={query}",
+  "youtube":       "https://www.youtube.com/results?search_query={query}",
+  "yt":            "https://www.youtube.com/results?search_query={query}",
+  "spotify":       "https://open.spotify.com/search/{query}",
+  "amazon":        "https://www.amazon.com/s?k={query}",
+  "ecosia":        "https://www.ecosia.org/search?q={query}",
+  "furaffinity":   "https://www.furaffinity.net/search/?q={query}",
+  "fa":            "https://www.furaffinity.net/search/?q={query}",
+  "bing":          "https://www.bing.com/search?q={query}",
+  "github":        "https://github.com/search?q={query}",
+  "wikipedia":     "https://en.wikipedia.org/wiki/Special:Search?search={query}",
+  "wiki":          "https://en.wikipedia.org/wiki/Special:Search?search={query}",
+  "reddit":        "https://www.reddit.com/search/?q={query}",
+  "stackoverflow": "https://stackoverflow.com/search?q={query}",
+  "so":            "https://stackoverflow.com/search?q={query}",
+}
+
+DISPLAY_NAMES = {
+  "google": "Google", "brave": "Brave Search", "duckduckgo": "DuckDuckGo",
+  "ddg": "DuckDuckGo", "youtube": "YouTube", "yt": "YouTube",
+  "spotify": "Spotify", "amazon": "Amazon", "ecosia": "Ecosia",
+  "furaffinity": "FurAffinity", "fa": "FurAffinity", "bing": "Bing",
+  "github": "GitHub", "wikipedia": "Wikipedia", "wiki": "Wikipedia",
+  "reddit": "Reddit", "stackoverflow": "Stack Overflow", "so": "Stack Overflow",
+}
+
+SUBCOMMANDS = [
+  ("google",        "Search with Google."),
+  ("brave",         "Search with Brave Search."),
+  ("duckduckgo",    "Search with DuckDuckGo."),
+  ("ddg",           "Search with DuckDuckGo (alias for duckduckgo)."),
+  ("youtube",       "Search YouTube videos."),
+  ("yt",            "Search YouTube (alias for youtube)."),
+  ("spotify",       "Search Spotify."),
+  ("amazon",        "Search Amazon."),
+  ("ecosia",        "Search with Ecosia."),
+  ("furaffinity",   "Search FurAffinity."),
+  ("fa",            "Search FurAffinity (alias for furaffinity)."),
+  ("bing",          "Search with Bing."),
+  ("github",        "Search GitHub."),
+  ("wikipedia",     "Search Wikipedia."),
+  ("wiki",          "Search Wikipedia (alias for wikipedia)."),
+  ("reddit",        "Search Reddit."),
+  ("stackoverflow", "Search Stack Overflow."),
+  ("so",            "Search Stack Overflow (alias for stackoverflow)."),
+]