One-click return improvement

[Jambeeno]

One-click returns are only reliably offered if expanding the chain of a highlighted tab made from a specific system in the Chain map panel (i.e. if moving “down chain” relative to one highlighted system).

Jumping systems with a K-Space tab highlighted sometimes doesn’t offer OCRs. Jumping from KS → JS with a K-Space tab highlighted does, but jumping KS → KS doesn't).

If OCRs were triggered simply by pasting sigs into a system with one blank connected wormhole entry in it (i.e. the automatically created ???-### one), that’d (presumably) make OCRs always always available in new systems, which would be nice.

To address situations in which there are preexisting sigless connections in the new system (i.e. how can TW tell which ???-### should be connected via OCR), one might default to connecting to the most recently-created ???-###, or pop up a “Which Signature?” window as is already the case with multiple outholes (except the options for differentiating inholes would have blank sigs and non-blank Leads Tos instead of vice-versa).