C-grade round-1 blockers fixed:
- [HIGH] retention default 14d → 30d to match engine (health-checker.js:34)
- [MEDIUM] phantom 'Settings → Disk Safety' path removed
- [MEDIUM] dangling 'stats polling interval' bullet (no such control in modal)
- [LOW] exaggerated 'hundreds of MB' → 'tens of MB'
- [LOW] button label mismatch (real button is '💾 Disk')
GLM round 2 verified all 5 fixes landed; no new regressions; HTML balanced.
Pre-existing follow-up parked: disk-settings.json saved values not reloaded by engine on container restart (out of scope for this commit).