Polish narrow responsive navigation

[jonashertner]

Outcome

Finishes the live-responsive review before publishing the two-surface workspace to the canonical host.

• increases the usable evidence area on 320×568 screens from 89px to 127px while preserving the full map
• adds quiet, state-aware continuation cues to horizontally scrolling mode rails
• shows both directions while the rail is between its endpoints and clears each cue at the corresponding edge
• advances CSS and JavaScript cache keys
• adds release contracts for the smallest-phone allocation and rail discoverability

Chrome verification

Verified at 320×568, 390×844, 430×932, 844×390, 768×1024, 1024×768, 1280×800, 1440×900, 1920×1080 and 2048×1280. Also verified DE, EN, FR, IT and RM at 320×568 and 844×390. Every case has zero document overflow and zero map/workspace overlap.

Release verification

• npm run release
• npm run check:links — 79 checked, 0 dead, 0 inconclusive
• npm audit --json — 0 vulnerabilities
• git diff --check