Go envelope v1.160 — stronger Janus lockup

Strengthens the horizontal Janus brand lockup.

• doubles the visible contour weight of the canonical faces-only SVG
• expands the SVG viewBox so the heavier contour remains unclipped
• keeps the facial details open at the 31px production size
• raises the separate JANUS wordmark to semibold (600)
• preserves the centered Pharos-family lockup geometry