全能创作：定妆/台词/换款与剧情方向硬约束，资源可下载

修角色定妆修改不重出图、角色图混入商品、宠物旁白腔、换款同点复读、剧情反转方向漂移，并补会话资源下载与外观/空消息闸门。

core/frontend/src/omni-session-page.css

@@ -2527,9 +2527,10 @@
   box-shadow: -8px 12px 40px rgba(20, 27, 38, .16);
 }
 
-.omni-prompt-drawer header {
+.omni-prompt-drawer header,
+.omni-prompt-drawer-head {
   display: grid;
-  grid-template-columns: 36px minmax(0, 1fr) 32px;
+  grid-template-columns: 36px minmax(0, 1fr) 32px 32px;
   align-items: center;
   gap: 10px;
   padding: 14px 14px 12px;
@@ -2552,29 +2553,35 @@
   height: 16px;
 }
 
-.omni-prompt-drawer header div {
+.omni-prompt-drawer header div,
+.omni-prompt-drawer-head div {
   min-width: 0;
 }
 
 .omni-prompt-drawer header strong,
-.omni-prompt-drawer header small {
+.omni-prompt-drawer header small,
+.omni-prompt-drawer-head strong,
+.omni-prompt-drawer-head small {
   display: block;
 }
 
-.omni-prompt-drawer header strong {
+.omni-prompt-drawer header strong,
+.omni-prompt-drawer-head strong {
   overflow: hidden;
   font-size: 15px;
   text-overflow: ellipsis;
   white-space: nowrap;
 }
 
-.omni-prompt-drawer header small {
+.omni-prompt-drawer header small,
+.omni-prompt-drawer-head small {
   margin-top: 2px;
   color: #8b919a;
   font-size: 12px;
 }
 
-.omni-prompt-drawer header button {
+.omni-prompt-drawer header button,
+.omni-prompt-drawer-head button {
   width: 32px;
   height: 32px;
   display: grid;
@@ -3188,6 +3195,149 @@
   font-size: 11px;
 }
 
+/* 对话资源 / 文档卡下载 */
+.omni-doc-head-actions {
+  display: inline-flex;
+  align-items: center;
+  gap: 8px;
+  flex: 0 0 auto;
+}
+
+.omni-doc-download {
+  flex: 0 0 auto;
+  width: 32px;
+  height: 32px;
+  display: grid;
+  place-items: center;
+  border: 1px solid var(--border-faint);
+  border-radius: 8px;
+  background: var(--surface);
+  color: var(--accent-black);
+  cursor: pointer;
+  transition: background var(--t-base), border-color var(--t-base), color var(--t-base);
+}
+
+.omni-doc-download:hover {
+  border-color: var(--border-loud);
+  background: var(--background-lighter);
+  color: var(--klein);
+}
+
+.omni-doc-download svg {
+  width: 14px;
+  height: 14px;
+}
+
+.omni-prompt-file-actions {
+  display: flex;
+  flex: 0 0 auto;
+  align-items: center;
+  gap: 8px;
+}
+
+.omni-prompt-file-actions button {
+  display: inline-flex;
+  align-items: center;
+  gap: 6px;
+}
+
+.omni-prompt-file-actions button.is-secondary {
+  background: transparent;
+  border: 1px solid var(--border-faint);
+  color: var(--accent-black);
+}
+
+.omni-prompt-file-actions button svg {
+  width: 14px;
+  height: 14px;
+}
+
+.omni-assets-card {
+  position: relative;
+}
+
+.omni-assets-card-main {
+  display: flex;
+  flex: 1;
+  min-width: 0;
+  flex-direction: column;
+  gap: 8px;
+  padding: 0;
+  border: 0;
+  background: transparent;
+  color: inherit;
+  text-align: left;
+  width: 100%;
+  cursor: pointer;
+}
+
+.omni-assets-card.is-doc .omni-assets-card-main,
+.omni-assets-grid.is-list .omni-assets-card-main {
+  flex-direction: row;
+  align-items: center;
+  gap: 10px;
+}
+
+.omni-assets-card-main:disabled {
+  cursor: default;
+  opacity: .72;
+}
+
+.omni-assets-dl {
+  position: absolute;
+  right: 8px;
+  bottom: 8px;
+  z-index: 1;
+  width: 28px;
+  height: 28px;
+  display: grid;
+  place-items: center;
+  border: 0;
+  border-radius: 8px;
+  color: #fff;
+  background: rgba(16, 16, 18, .72);
+  cursor: pointer;
+  opacity: 0;
+  pointer-events: none;
+  transition: opacity .16s ease;
+}
+
+.omni-assets-card.is-doc .omni-assets-dl,
+.omni-assets-grid.is-list .omni-assets-dl {
+  position: static;
+  flex: 0 0 auto;
+  margin-left: auto;
+  color: var(--accent-black);
+  background: var(--background-lighter);
+  opacity: 1;
+  pointer-events: auto;
+}
+
+.omni-assets-card:hover .omni-assets-dl,
+.omni-assets-dl:focus-visible {
+  opacity: 1;
+  pointer-events: auto;
+}
+
+.omni-assets-dl:disabled {
+  opacity: .4;
+  cursor: default;
+  pointer-events: none;
+}
+
+.omni-assets-dl svg {
+  width: 14px;
+  height: 14px;
+}
+
+@media (hover: none) {
+  .omni-assets-dl {
+    opacity: 1;
+    pointer-events: auto;
+  }
+}
+
+
 .omni-model-picker-grid {
   display: grid;
   grid-template-columns: repeat(2, minmax(0, 1fr));