hermes - 💡(How to fix) Fix concurrency: four TOCTOU races in browser_tool.py lazy-init singletons

Bug

Four resolver functions in tools/browser_tool.py share the same TOCTOU pattern: the resolved flag is set to True before the cached value is computed or written. A concurrent thread hitting the early-return fast path in the window between the flag write and the value write reads a stale default.

Affected functions and the impact of a stale read:

Example pattern (all four look like this):

_command_timeout_resolved = True      # ← flag set first
result = DEFAULT_COMMAND_TIMEOUT
# … config read …
_cached_command_timeout = result      # ← value written last

Fix

Apply double-checked locking to each: add per-function threading.Locks, fast path remains lock-free after first init, value written before resolved flag inside the lock.