Fix curved edges

[vagkaratzas]

Changed

• Channel curvature sliders reach much further — intra-layer 10–60 (was 10–20), inter-layer 1–30 (was 1–10) — so the channels of a multi-channel edge can be pulled well apart instead of running nearly parallel. Defaults are unchanged, so existing sessions render exactly as before.

Fixed

• Edges no longer glow. Thick edges cover a large share of the screen, and bloom on all of them was blinding against dark backgrounds. Bloom is now selective (three's off-screen bloom-composer pattern): edges render on a dedicated layer that the bloom source masks out, so nodes still glow and edges stay crisp.
• Curved channel edges rendered as dotted lines with beads at the curve points once thickness landed. LineMaterial's worldUnits mode assumes a perspective camera — its fragment shader traces a view ray from the camera origin and discards anything farther than half a width from the segment, which under this app's orthographic camera discards along the whole segment. Widths are now screen-space, sized against a shared resolution uniform kept on the frustum size (so the numbers still mean world units), retargeted on resize and for the PNG export.