feat: compact breadcrumb menu + 'X more' Notion-style in workspace

1. Compact breadcrumb hover menu:
   - Reduced font-size: header-breadcrumb 14→13px, breadcrumb-link 14→13px
   - Dropdown menus: fd-nav-menu min-width 240→200px, padding reduced
   - fd-nav-item: padding 6px8→4px6, font 14→13px, gap 8→6px
   - fd-nav-section: font 11→10px, padding reduced
   - fd-nav-ico: size 16→14px, width 20→18px
   - fd-nav-arrow: size 16→14px, margin-left 4→2px

2. 'X more' Notion-style (tree view):
   - Shows first 5 items in displayTree, hides rest
   - 6th item shows 'X more...' with count of remaining items
   - Click to expand and show all items
   - 'Show less' button to collapse back to 5
   - showAll state auto-resets on folder navigation, sort, filter
   - Styling: semi-transparent hover effect on ws-more-item

static/css/app.css

@@ -844,7 +844,7 @@ input, select, textarea { font-family: inherit; color: inherit; }
   display: flex;
   align-items: center;
   gap: 2px;
-  font-size: 14px;
+  font-size: 13px;
   overflow: visible;
   flex: 1;
   min-width: 0;
@@ -880,7 +880,7 @@ input, select, textarea { font-family: inherit; color: inherit; }
   border: none;
   background: transparent;
   font: inherit;
-  font-size: 14px;
+  font-size: 13px;
   line-height: 1.4;
   cursor: pointer;
   border-radius: 4px;
@@ -932,25 +932,25 @@ button.breadcrumb-current { max-width: 260px; }
   position: absolute;
   top: calc(100% + 4px);
   left: 0;
-  min-width: 240px;
-  max-width: 320px;
+  min-width: 200px;
+  max-width: 280px;
   overflow: visible;
   background: var(--bg-modal, #fff);
   border: 1px solid var(--border);
   border-radius: var(--radius-lg, 8px);
   box-shadow: var(--shadow-popover, 0 6px 24px rgba(0,0,0,0.25));
   z-index: 2000;
-  padding: 6px;
+  padding: 4px;
 }
 
 .fd-nav-submenu {
-  top: -6px;
+  top: -4px;
   left: calc(100% + 2px);
 }
 
 .fd-nav-section {
-  padding: 4px 8px 6px;
-  font-size: 11px;
+  padding: 3px 8px 4px;
+  font-size: 10px;
   font-weight: 600;
   letter-spacing: 0.02em;
   color: var(--text-tertiary);
@@ -958,8 +958,8 @@ button.breadcrumb-current { max-width: 260px; }
 }
 
 .fd-nav-empty {
-  padding: 8px 10px;
-  font-size: 13px;
+  padding: 6px 8px;
+  font-size: 12px;
   color: var(--text-tertiary);
 }
 
@@ -967,10 +967,10 @@ button.breadcrumb-current { max-width: 260px; }
   position: relative;
   display: flex;
   align-items: center;
-  gap: 8px;
-  padding: 6px 8px;
+  gap: 6px;
+  padding: 4px 6px;
   border-radius: 6px;
-  font-size: 14px;
+  font-size: 13px;
   color: var(--text-primary);
   cursor: pointer;
   white-space: nowrap;
@@ -982,8 +982,8 @@ button.breadcrumb-current { max-width: 260px; }
 }
 
 .fd-nav-ico {
-  font-size: 16px;
-  width: 20px;
+  font-size: 14px;
+  width: 18px;
   text-align: center;
   flex-shrink: 0;
 }
@@ -996,9 +996,9 @@ button.breadcrumb-current { max-width: 260px; }
 
 .fd-nav-arrow {
   color: var(--text-tertiary);
-  font-size: 16px;
+  font-size: 14px;
   flex-shrink: 0;
-  margin-left: 4px;
+  margin-left: 2px;
 }
 
 /* ── Dropdown panel (reusable) ── */