Port labels: render outside the block, no more chunky expansion

[milanofthe]

• Port labels render as absolutely-positioned spans outside the block bounds — block size stays the same whether labels are toggled on or off
• For vertical block orientations, labels use writing-mode: sideways-{lr|rl} to read parallel to the wire (top edge bottom-to-top, bottom edge top-to-bottom — both reading outward from the block)
• The handle/wire is always below the label from the label's perspective; anchor sits at label's bottom-left or bottom-right
• Hover over a port handle highlights the matching label in the node accent color; same accent applies when the block is selected
• Tooltip on handle hover is suppressed when the label is already visible (no double-info)
• applyPortLabelSync runs recursively on model load so Scope/Spectrum/Adder/Divider port names match their labels/operations params from the start (previously synced only on the next param edit)