Add cursor:pointer to [data-bw-action] elements in bitwrench.css

[deftio]

Problem

Any element with data-bw-action is clickable -- bwclient.js wires click handlers on them. But there's no visual indication that they're interactive. No cursor change, no hover state.

This means:

• Users don't know non-button elements are clickable
• Developers must manually add cursor: pointer to every action element
• Automated testing tools can't distinguish clickable from static elements without parsing attributes

Proposed Fix

One line in bitwrench.css:

[data-bw-action] { cursor: pointer; }

Optionally, a subtle hover effect:

[data-bw-action]:hover { opacity: 0.85; }