Port asset selectors — accept several data-asset types on one port

The port's asset-type picker is the real shared Combobox below (live from the bundle — open it, type, pick). The only UI delta of this feature: the Categories group of selector entries on top of the existing Files/Folders/Tables groups. Ports on the canvas are untouched; connection rejection reuses the existing popup, only the expected-type label can now be a selector label.

1 · datalink port (wire-facing) — Categories group added

The untouched shared control — the feature only feeds it different options (a new "Categories" group from asset_selectors, plain labels — member counts were considered and rejected).

2 · dataasset port (scratch carrier) — unchanged, concrete types only

The port that materializes a scratch asset must stay concrete — no Categories group here. Same control, filtered options.