revert: !68 risefor-img min-content floor (falsified theory, potential card side-effect)

Reverts !68 (merged) (min-height: min-content on .risefor-img).

Why: !68 (merged) shipped under the height-cycle theory of the iOS header bug, which has since been falsified (the logo markup/CSS never changed in !65 (merged), yet the cut only appeared after it — Catalyst's timeline analysis). The real root was the orbit-shell double-scroll container, fixed in !70 (merged).

Why revert rather than keep: the declaration isn't provably inert. A min-content floor on a height: 100% box could let oversized images render taller than the fixed-height card headers (170px action banner / rep avatar) in some content states. My !68 (merged) verification only covered the header logo and one card — not enough to call it safe. With the real fix shipped and !68 (merged)'s mechanism dead, carrying an unverified layout override serves no purpose.

Pure revert of 54fea485 (−7 lines, one declaration). Zero interaction with !65 (merged)/!66 (merged)/!70 (merged) — they touch different rules.