Enable a progressively larger subset of ruff rules for logical issues

We could enable some linting rules for things that look like real bugs. A few high signal-to-noise ones could be:

• PLW0177 - we have a few checks with == np.nan that always evaluate to False and are thus pointless
• B006 - mutable default args, easy to fix
• B904 - better exception chaining
• PLW2910 - loop var overwritten, a bit suspicious, 10 hits

Others to investigate: PLE / RSE, FLY, PIE810.

Other rules which probably make sense only after enabling ruff format, but which are probably lower-priority:

• UP (pyupgrade), urles are largely auto-fixable (hurrah)
• SIM (simplify) - often useful
• RET - avoid returning None implicitly. Perhaps a longer-term goal, as lots of resqpy functions