Simplify download folder browser by removing manual path rows and preserving scroll position

- Remove 'Use model root' and 'Use typed folder' manual rows from the folder browser
- Remove category badge and folder browser header elements
- Add nested scroll element detection for scroll delta handling
- Preserve scroll position when re-rendering the folder browser on toggle

web/css/resolver-main.css

@@ -5690,23 +5690,6 @@
     overflow: hidden;
     padding: 0;
 }
-.mr-folder-browser-head {
-    display: flex;
-    align-items: flex-start;
-    justify-content: space-between;
-    gap: 12px;
-    padding: 10px 12px;
-    border-bottom: 1px solid rgba(255,255,255,0.075);
-    background: rgba(255,255,255,0.025);
-}
-.mr-folder-browser-title {
-    color: var(--mr-text);
-    font-size: 12px;
-    font-weight: 750;
-    line-height: 1.25;
-}
-.mr-folder-browser-subtitle,
-.mr-folder-browser-category,
 .mr-folder-browser-preview-label,
 .mr-folder-browser-root-path,
 .mr-folder-browser-count,
@@ -5715,16 +5698,6 @@
     font-size: 10px;
     line-height: 1.3;
 }
-.mr-folder-browser-category {
-    max-width: 160px;
-    padding: 3px 7px;
-    border: 1px solid rgba(255,255,255,0.09);
-    border-radius: 999px;
-    background: rgba(255,255,255,0.035);
-    white-space: nowrap;
-    overflow: hidden;
-    text-overflow: ellipsis;
-}
 .mr-folder-browser-preview {
     display: grid;
     gap: 3px;
@@ -5750,8 +5723,7 @@
 .mr-folder-browser-root + .mr-folder-browser-root {
     margin-top: 6px;
 }
-.mr-folder-browser-root-head,
-.mr-folder-browser-manual {
+.mr-folder-browser-root-head {
     width: 100%;
     border: 0;
     color: var(--mr-text);
@@ -5767,7 +5739,6 @@
     padding: 6px 8px;
 }
 .mr-folder-browser-root-head:hover,
-.mr-folder-browser-manual:hover,
 .mr-folder-browser-row:hover {
     background: rgba(114,211,138,0.095);
 }
@@ -5874,22 +5845,6 @@
     border-radius: 999px;
     background: rgba(255,255,255,0.045);
 }
-.mr-folder-browser-manual {
-    display: grid;
-    gap: 2px;
-    padding: 8px 12px;
-    border-bottom: 1px solid rgba(255,255,255,0.06);
-}
-.mr-folder-browser-manual-title {
-    color: var(--mr-text);
-    font-size: 11px;
-    font-weight: 700;
-}
-.mr-folder-browser-manual-path {
-    color: var(--mr-text-muted);
-    font-size: 10px;
-    word-break: break-all;
-}
 .mr-folder-browser-empty {
     padding: 24px 12px;
     color: var(--mr-text-muted);