fix: element name empty string fallback + perf: remove redundant notifyParent

[SukuWc]

Changes

1. Fix element name not rendering auto-generated value when set to empty string

When an element's name store held "" instead of undefined, the auto-generated fallback name (e.g. "Element 0 (Encoder)") was not rendered.

• Configuration.svelte: Changed el.name = "" to el.name = undefined when the name block is removed, matching the type definition (string | undefined) and what resetName() does.
• ElementSelectionPanel.svelte: Added !== "" guard alongside the existing typeof !== "undefined" check so empty strings also fall through to getHumanName().

2. Perf: Remove redundant notifyParent in setField

setField called this.update() (which already calls notifyParent()), then called notifyParent() again — every field change fired two full walks up the runtime tree instead of one.

This halved store notification traffic across the entire codebase. Particularly impactful for the element name textbox, where updateData changes 4-5 fields per keystroke, each previously triggering ~2 walks x 5 tree levels.