v0.3.1 - tuned shell regex from real session data

Narrows the shell-event beep to only truly elevated tokens (sudo, ssh family, chmod, chown) and anchors matching to the start of a (sub-)command so paths in arguments (e.g. ~/.ssh/config) stop triggering the ssh token.

Tuned from a real ~3-hour multi-agent session diagnostic log:

• 28 noise items previously beeping (all git, uv, curl, ~/.ssh/ path reads) now silent.
• All 10 legit SSH-key/host setup operations still beep.
• Zero spurious MCP beeps observed; MCP coverage unchanged.
• stop event remains the primary 'agent needs you' signal, as before.

To override the tokens for your own workflow:

export ATTENTION_BEEP_PATTERN='your-extended-regex'

Or restore the v0.3.0 token set by exporting the previous default.