fix(spacing): symmetric internal padding in Dialog, Card, Tour, confirm-popover

[Mini-Sylar]

Summary

• Dialog and Card's body→footer gap was silently double-counted against header→body (both sides added padding for the same transition instead of one owning it), making it exactly 2x header→body. Fixed by letting the footer alone own the gap, matching how header→body already works.
• Tour had the same double-count on description→actions, plus its own header/actions padding was stacking on top of Popover's shared .ui-popover-body padding (1rem), doubling the outer margin (2rem effective edge vs 0.5rem interior — a ~4:1 ratio). Zeroed Popover's body padding specifically when it wraps Tour content, so Tour's own padding is the single source of outer spacing.
• confirmAction's popover surface (shared/confirm-popover.css) had no edge padding of its own — all of it came from Popover's shared 1rem — with interior gaps too tight relative to that (previously 0.35rem/0.6rem asymmetric, briefly over-corrected to a too-tight uniform 0.25rem). Now 0.5rem, matching the same 2:1 edge-to-interior ratio Tour uses in the same Popover body.

All four now follow one consistent, deliberate 2:1 edge-to-interior ratio, with every transition owned by exactly one side.

Verification

• Real rendered measurement (Playwright) at true 16px root font-size (the docs site itself renders at 14px, which was a confound during review): Dialog header→body and body→footer both measured exactly 12px. Tour's interior gaps measured exactly equal both sides, and its outer margin dropped from double (32px) to single (16px) after the Popover body-padding fix.
• Full monorepo pnpm build, pnpm typecheck:only, and pnpm --filter vael-ui test (691/691) all pass clean from a from-scratch rebuild.

Test plan

• pnpm build (root) — clean
• pnpm typecheck:only — clean
• pnpm --filter vael-ui test — 691/691 passed
• Real Playwright render + pixel measurement of Dialog and Tour at true 16px root