fix(core): chat-panel ui (#10928)

Close [AF-2332](https://linear.app/affine-design/issue/AF-2332).
Close [AF-2333](https://linear.app/affine-design/issue/AF-2333).

packages/frontend/core/src/blocksuite/ai/chat-panel/components/add-popover.ts

@@ -147,7 +147,9 @@ export class ChatPanelAddPopover extends SignalWatcher(
           height="30px"
           data-id="upload"
           .text=${'Upload files (pdf, txt, csv)'}
+          hover=${this._activatedItemIndex === items.length + 1}
           @click=${this._addFileChip}
+          @mousemove=${() => (this._activatedItemIndex = items.length + 1)}
         >
           ${UploadIcon()}
         </icon-button>

packages/frontend/core/src/blocksuite/ai/chat-panel/components/chip.ts

@@ -31,6 +31,11 @@ export class ChatPanelChip extends SignalWatcher(
       color: var(--affine-error-color);
       background: var(--affine-background-error-color);
     }
+    .chip-card-content {
+      display: flex;
+      align-items: center;
+      justify-content: center;
+    }
     .chip-card[data-state='failed'] svg {
       color: var(--affine-error-color);
     }
@@ -92,11 +97,13 @@ export class ChatPanelChip extends SignalWatcher(
         data-testid="chat-panel-chip"
         data-state=${this.state}
       >
-        ${this.icon}
-        <span class="chip-card-title" @click=${this.onChipClick}>
+        <div class="chip-card-content">
+          ${this.icon}
+          <span class="chip-card-title" @click=${this.onChipClick}>
+            <span data-testid="chat-panel-chip-title">${this.name}</span>
+          </span>
           <affine-tooltip>${this.tooltip}</affine-tooltip>
-          <span data-testid="chat-panel-chip-title">${this.name}</span>
-        </span>
+        </div>
         ${this.closeable
           ? html`
               <div class="chip-card-close" @click=${this.onChipDelete}>