Fix security and reliability audit findings

[godhiraj-code]

Navigation reinjection could sleep for the full polling interval beyond a shorter per-call timeout.

Validation: 168 passed in 0.39s

Remaining validation or scope limits:

• Real-browser Selenium integration tests pending; unit/runtime instrumentation tests included where available.
• Validation on Windows Python 3.13; the full CI OS/Python matrix was not executed locally.
• Repository workflows reviewed; most CI actions are tag-pinned and many workflows inherit token permissions. Release/branch-protection settings were not changed.