Browser detection and executable path resolution fixes

Fixes on record

Merged to main. A stamp counts the issues a fix is linked to.

• #19595 fix: _chromium_installed() honors AGENT_BROWSER_EXECUTABLE_PATH and system Chrome

  merged to main

  files: tools/browser_tool.py

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  • tools/browser_tool.py

    @@ -2757,17 +2757,40 @@ def _chromium_search_roots() -> List[str]:
     def _chromium_installed() -> bool:
         """Return True when a usable Chromium (or headless-shell) build is on disk.
     
    +    Checks, in order:
    +
    +    1. ``AGENT_BROWSER_EXECUTABLE_PATH`` env var — the official way to point
    +       agent-browser at a pre-installed Chrome/Chromium.
    +    2. System Chrome/Chromium in PATH (``google-chrome``, ``chromium-browser``,
    +       ``chrome``).
    +    3. Playwright's browser cache (current logic) — directories containing
    +       ``chromium-*`` or ``chromium_headless_shell-*``.
    +
         agent-browser (0.26+) downloads Playwright's chromium / headless-shell
    -    builds into ``PLAYWRIGHT_BROWSERS_PATH`` and won't start without them.
    -    When the CLI is present but no browser build is, the first browser tool
    -    call hangs for the full command timeout (often ~30s each) before
    -    surfacing a useless error. Guarding the tool behind this check prevents
    -    advertising a capability that will fail at runtime.
    +    builds into ``PLAYWRIGHT_BROWSERS_PATH`` and won't start without at least
    +    one of the three above being present.  Without a browser binary the CLI
    +    hangs on first use until the command timeout fires (often ~30s).  Guarding
    +    the tool behind this check prevents advertising a capability that will
    +    fail at runtime.
         """
         global _cached_chromium_installed
         if _cached_chromium_installed is not None:
             return _cached_chromium_installed
     
    +    # 1. AGENT_BROWSER_EXECUTABLE_PATH — explicit user-configured browser
    +    ab_path = os.environ.get("AGENT_BROWSER_EXECUTABLE_PATH", "").strip()
    +    if ab_path:
    +        if os.path.isfile(ab_path) or shutil.which(ab_path):
    +            _cached_chromium_installed = True
    +            return True
    +
    +    # 2. System Chrome/Chromium in PATH (common names)
    +    system_chrome = shutil.which("google-chrome") or shutil.which("chromium-browser") or shutil.which("chrome")
    +    if system_chrome:
    +        _cached_chromium_installed = True
    +        return True
    +
    +    # 3. Playwright browser cache (legacy — chromium-* / chromium_headless_shell-* dirs)
         for root in _chromium_search_roots():
             if not root or not os.path.isdir(root):
                 continue

• #33184 fix(docker): discover agent-browser Chromium binary at boot

  merged to main

  files: docker/stage2-hook.sh