fix(FN-2646): restore quick chat render toggle visibility

- Remove generic btn btn-icon classes from quick chat render toggles so component-specific visibility styles apply
- Increase toggle icon size and adjust default muted color for clearer eye/eye-off affordance in assistant messages
- Add explicit focus-visible ring styling for keyboard accessibility on the render toggle control
- Extend QuickChatFAB regression coverage to assert class usage, SVG icon presence, and plain/rendered toggle state transitions

packages/dashboard/app/components/QuickChatFAB.css

@@ -293,11 +293,12 @@
   justify-content: center;
   opacity: 0;
   transition: opacity var(--transition-fast);
-  color: var(--text-tertiary);
+  color: var(--text-muted);
   background: transparent;
   border: none;
   border-radius: var(--radius-sm);
   cursor: pointer;
+  outline: none;
 }
 
 .quick-chat-panel-message--received:hover .quick-chat-message-render-toggle,
@@ -315,6 +316,11 @@
   color: var(--text);
 }
 
+.quick-chat-message-render-toggle:focus-visible {
+  outline: none;
+  box-shadow: var(--focus-ring-strong);
+}
+
 .quick-chat-panel-input {
   display: flex;
   align-items: center;

packages/dashboard/app/components/QuickChatFAB.tsx

@@ -1349,12 +1349,12 @@ export function QuickChatFAB({
                             {renderAssistantMessageContent(message.content, forcePlain)}
                             <button
                               type="button"
-                              className={`btn btn-icon quick-chat-message-render-toggle${forcePlain ? " quick-chat-message-render-toggle--plain" : ""}`}
+                              className={`quick-chat-message-render-toggle${forcePlain ? " quick-chat-message-render-toggle--plain" : ""}`}
                               data-testid="quick-chat-message-render-toggle"
                               aria-label={forcePlain ? "Show rendered markdown" : "Show plain text"}
                               onClick={() => toggleMessageRenderMode(message.id)}
                             >
-                              {forcePlain ? <EyeOff size={12} /> : <Eye size={12} />}
+                              {forcePlain ? <EyeOff size={14} /> : <Eye size={14} />}
                             </button>
                           </>
                         )}
@@ -1375,12 +1375,12 @@ export function QuickChatFAB({
                         </div>
                         <button
                           type="button"
-                          className={`btn btn-icon quick-chat-message-render-toggle${plainTextMessageIds.has("__streaming__") ? " quick-chat-message-render-toggle--plain" : ""}`}
+                          className={`quick-chat-message-render-toggle${plainTextMessageIds.has("__streaming__") ? " quick-chat-message-render-toggle--plain" : ""}`}
                           data-testid="quick-chat-message-render-toggle"
                           aria-label={plainTextMessageIds.has("__streaming__") ? "Show rendered markdown" : "Show plain text"}
                           onClick={() => toggleMessageRenderMode("__streaming__")}
                         >
-                          {plainTextMessageIds.has("__streaming__") ? <EyeOff size={12} /> : <Eye size={12} />}
+                          {plainTextMessageIds.has("__streaming__") ? <EyeOff size={14} /> : <Eye size={14} />}
                         </button>
                       </>
                     ) : (

packages/dashboard/app/components/__tests__/QuickChatFAB.test.tsx

@@ -248,16 +248,21 @@ describe("QuickChatFAB", () => {
 
     const toggles = screen.getAllByTestId("quick-chat-message-render-toggle");
     expect(toggles).toHaveLength(2);
+    expect(toggles[0]).not.toHaveClass("btn");
+    expect(toggles[0]).not.toHaveClass("btn-icon");
+    expect(toggles[0].querySelector("svg")).toBeInTheDocument();
     expect(within(firstAssistantBubble).getByText("Bold", { selector: "strong" })).toBeInTheDocument();
     expect(within(secondAssistantBubble).getByText("Bold", { selector: "strong" })).toBeInTheDocument();
 
     fireEvent.click(toggles[0]);
 
+    expect(toggles[0]).toHaveClass("quick-chat-message-render-toggle--plain");
     expect(within(firstAssistantBubble).getByText(/\*\*Bold\*\* one/)).toBeInTheDocument();
     expect(within(firstAssistantBubble).queryByText("Bold", { selector: "strong" })).toBeNull();
     expect(within(secondAssistantBubble).getByText("Bold", { selector: "strong" })).toBeInTheDocument();
 
     fireEvent.click(toggles[0]);
+    expect(toggles[0]).not.toHaveClass("quick-chat-message-render-toggle--plain");
     expect(within(firstAssistantBubble).getByText("Bold", { selector: "strong" })).toBeInTheDocument();
     expect(within(userBubble).getByText(/\*\*User\*\* plain/)).toBeInTheDocument();
   });