feat: update knowledge and agent UI

frontend-web/src/components/knowledge-graph/graphStyles.css

@@ -205,12 +205,39 @@
   flex-shrink: 0;
 }
 
+.kg-panel-header-actions {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  min-width: 0;
+}
+
 .kg-panel-title {
   font-size: 14px;
   font-weight: 700;
   color: var(--kg-text-main);
 }
 
+.kg-panel-close-btn {
+  width: 28px;
+  height: 28px;
+  border-radius: 8px;
+  border: 1px solid rgba(148, 163, 184, 0.18);
+  background: rgba(15, 23, 42, 0.65);
+  color: #94a3b8;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  cursor: pointer;
+  flex-shrink: 0;
+}
+
+.kg-panel-close-btn:hover {
+  color: #ffffff;
+  background: rgba(56, 189, 248, 0.14);
+  border-color: rgba(56, 189, 248, 0.35);
+}
+
 .kg-panel-content {
   padding: 14px;
   overflow-y: auto;
@@ -267,15 +294,44 @@
 }
 
 .kg-filter-section {
-  margin-top: 18px;
+  border-top: 1px solid rgba(148, 163, 184, 0.1);
+  padding: 10px 0;
 }
 
-.kg-filter-title {
-  font-size: 12px;
+.kg-filter-section:first-of-type {
+  margin-top: 12px;
+}
+
+.kg-filter-section-header {
+  width: 100%;
+  height: 34px;
+  border: none;
+  background: transparent;
+  color: #cbd5e1;
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  cursor: pointer;
+  padding: 0;
+  font-size: 13px;
   font-weight: 700;
-  color: var(--kg-text-secondary);
-  margin-bottom: 8px;
-  letter-spacing: 0.02em;
+}
+
+.kg-filter-section-header:hover {
+  color: #ffffff;
+}
+
+.kg-filter-section-extra {
+  color: #64748b;
+  font-size: 12px;
+  font-weight: 400;
+  display: inline-flex;
+  align-items: center;
+  gap: 4px;
+}
+
+.kg-filter-section-body {
+  padding-top: 8px;
 }
 
 .kg-check-row {
@@ -421,6 +477,14 @@
   overflow: hidden;
   min-width: 0;
   min-height: 0;
+  width: 100%;
+  height: 100%;
+}
+
+.kg-canvas-shell {
+  position: relative;
+  min-width: 0;
+  min-height: 0;
 }
 
 .kg-canvas {
@@ -485,6 +549,82 @@
   color: #ffffff;
 }
 
+.kg-explore-button {
+  height: 32px;
+  padding: 0 10px;
+  border-radius: 999px;
+  border: 1px solid rgba(148, 163, 184, 0.18);
+  background: rgba(15, 23, 42, 0.72);
+  color: #cbd5e1;
+  font-size: 12px;
+  cursor: pointer;
+  display: inline-flex;
+  align-items: center;
+  gap: 6px;
+  backdrop-filter: blur(12px);
+}
+
+.kg-explore-button:hover {
+  background: rgba(56, 189, 248, 0.14);
+  color: #ffffff;
+}
+
+.kg-explore-button:disabled {
+  opacity: 0.45;
+  cursor: not-allowed;
+}
+
+.kg-canvas-hint {
+  position: absolute;
+  left: 50%;
+  bottom: 22px;
+  z-index: 11;
+  transform: translateX(-50%);
+  max-width: min(560px, calc(100% - 48px));
+  padding: 8px 14px;
+  border-radius: 999px;
+  border: 1px solid rgba(56, 189, 248, 0.22);
+  background: rgba(15, 23, 42, 0.78);
+  color: #bae6fd;
+  font-size: 12px;
+  text-align: center;
+  backdrop-filter: blur(12px);
+  pointer-events: none;
+}
+
+.kg-side-rail-toggle {
+  position: absolute;
+  top: 50%;
+  z-index: 20;
+  width: 32px;
+  min-height: 88px;
+  border-radius: 12px;
+  border: 1px solid rgba(56, 189, 248, 0.28);
+  background: rgba(15, 23, 42, 0.86);
+  color: #bae6fd;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  writing-mode: vertical-rl;
+  letter-spacing: 4px;
+  cursor: pointer;
+  backdrop-filter: blur(12px);
+  transform: translateY(-50%);
+}
+
+.kg-side-rail-toggle-left {
+  left: 12px;
+}
+
+.kg-side-rail-toggle-right {
+  right: 12px;
+}
+
+.kg-side-rail-toggle:hover {
+  background: rgba(56, 189, 248, 0.16);
+  color: #ffffff;
+}
+
 .kg-minimap {
   position: absolute;
   right: 14px;