[0.9.1] FORK_IA_UX v5: drop 29 !important by replacing the CSS (no visual change)

Per feedback (avoid !important, substitute the CSS). Verified with computed-style
diffs on the real forum/chat DOM — layout is byte-identical.
- OasisMobile.css: 45 -> 23 !important. Removed the ones that only fought epsylon's
  NARROW rules; win by load-order/specificity instead (e.g. .forum-score-box
  .forum-score-form, .main-column .new-message-form). Kept the truly load-bearing
  ones (inline-style overrides [style*=...], round buttons vs the broad
  button{min-height:44px!important}, and comment-body-row vs mobile.css:164).
- mobile.css (FORK ONLY, user-authorized): removed !important from 7 narrow
  forum/chat rules (.forum-comment margin/padding, .comment-body-row flex-dir,
  .comment-vote/text-col width, .forum-score-* flex, .comment-textarea width) so
  our theme wins without !important. Not touched on UX_OASIS.

src/client/assets/styles/mobile.css

@@ -510,28 +510,28 @@ h3 { font-size: 1em !important; }
 }
 
 .forum-comment {
-  margin-left: 0 !important;
-  padding-left: 8px !important;
+  margin-left: 0;
+  padding-left: 8px;
 }
 
 .comment-body-row {
-  flex-direction: column !important;
+  flex-direction: column;
 }
 
 .comment-vote-col,
 .comment-text-col {
-  width: 100% !important;
+  width: 100%;
 }
 
 .forum-score-box,
 .forum-score-form {
-  flex-direction: row !important;
-  justify-content: center !important;
+  flex-direction: row;
+  justify-content: center;
 }
 
 .new-message-form textarea,
 .comment-textarea {
-  width: 100% !important;
+  width: 100%;
 }
 
 [style*="grid-template-columns: repeat(6"] {