Settings polish (2): duplicate New group

Seen on the live stack as an Org Admin (e2e-orgadmin-b) while verifying Task 6684. Fix each: 1. Settings > Tasks > Tags with no groups shows "New group" twice (card action and empty-state button). Keep one. 2. Settings > Infrastructure > Range starts at 390px: the summary line ("10 ports per project per service · slots 1 port apart · …") wraps with a dangling "·" at line ends. Leave no separator at the end of a line, or stack the facts one per line on phones. 3. Range starts with no rows leaves a tall empty block (~100px) under "No range starts — every var is auto-assigned." Make the empty state compact. 4. On desktop, a knob help tooltip (now placed to the right of its label) covers the row's own value. Consider a shorter max width or placing it over the value column's empty space so the value stays readable. Out of scope: which settings an org admin may edit; operator-only views; the onboarding bar. Done means: each item verified on the live stack as an Org Admin (screenshot per item, desktop and 390px where relevant); `./dc check full` green.

Fixed all 4 Settings items; checked live as an org admin at 1280px and 390px. Local full gate didn't pass: timed out at frontend vitest under host load, rerun killed for low memory. Merge lane ran full gate; PR #5635 merged. Deploy superseded by a newer one. Follow-ups: draft #6731.