Fix BYO first click lost to field hint shift (TASK-461)

frontend/src/v2/__tests__/V2AgentBYOName.test.tsx

@@ -79,6 +79,22 @@ afterEach(() => {
 });
 
 describe('BYO default agent name follows where it runs', () => {
+  test('pressing the connect action keeps the name field focused until click', async () => {
+    mockGet();
+    renderAt();
+    await waitFor(() => expect(screen.getByTestId('byo-mode-byo')).toBeInTheDocument());
+    fireEvent.click(screen.getByTestId('byo-mode-byo'));
+    const action = screen.getByRole('button', { name: /get my connect command/i });
+    await waitFor(() => expect(action).toBeEnabled());
+    nameInput().focus();
+    expect(nameInput()).toHaveFocus();
+    expect(fireEvent.mouseDown(action, { cancelable: true })).toBe(false);
+    expect(nameInput()).toHaveFocus();
+    const moreWays = screen.getByTestId('byo-more-ways').querySelector('summary');
+    expect(fireEvent.mouseDown(moreWays, { cancelable: true })).toBe(false);
+    expect(nameInput()).toHaveFocus();
+  });
+
   test('reconnect deep link keeps the name and rotates a revoked key with one action', async () => {
     mockGet([{ name: 'local', installedBy: 'u1', runtime: { runtimeType: 'webhook' },
       connection: { state: 'revoked', lastSeenAt: null } }]);

frontend/src/v2/__tests__/v2-layout-invariants.test.ts

@@ -213,6 +213,12 @@ describe('v2 layout invariants (CSS rule presence)', () => {
     expect(ruleBody(v2, '.v2-byo__hint')).toContain('margin: 0');
   });
 
+  test('BYO field hints take no space until focused or in error', () => {
+    expect(ruleBody(v2, '.v2-byo__field > .v2-byo__hint')).toContain('display: none');
+    expect(selectorRuleBody(v2, '.v2-byo__field:focus-within > .v2-byo__hint,\n.v2-byo__field--error > .v2-byo__hint'))
+      .toContain('display: block');
+  });
+
   // #2287 (QA BYO walk 1): "Other ways to connect" folds the alternatives so the
   // page shows one command, and the needs line is read before the Copy button.
   // jsdom cannot see either; sprint-review deleted all three rules and every

frontend/src/v2/components/V2AgentBYO.tsx

@@ -1201,7 +1201,8 @@ const V2AgentBYO: React.FC = () => {
               {t('agentByo.actions.chooseFirst')}
             </div>
           ) : canReconnect ? (
-              <button type="button" className="v2-byo__submit" disabled={submitting || !podId} onClick={() => {
+              <button type="button" className="v2-byo__submit" disabled={submitting || !podId}
+                onMouseDown={(event) => event.preventDefault()} onClick={() => {
                 if (existingConnection.runtimeType === 'wrapper') void requestMachineReconnect(sanitizeAgentName(name));
                 else void replaceRunningKey({ agentName: sanitizeAgentName(name), podId });
               }}>
@@ -1210,6 +1211,9 @@ const V2AgentBYO: React.FC = () => {
             ) : isOtherOwner ? null : (
             <button
               type="button"
+              // Keep the focused field's hint visible through the press. If blur
+              // hides it on mousedown, this button can move before mouseup.
+              onMouseDown={(event) => event.preventDefault()}
               onClick={submit}
               disabled={submitting || (mode === 'byo' && !namesReady) || !podId}
               className="v2-byo__submit"
@@ -1224,7 +1228,10 @@ const V2AgentBYO: React.FC = () => {
           {/* One command is THE path (QA BYO walk 1): the daemon and the SDK
               are real alternatives, but shown as equals beside the button they
               read as a choice a stranger has to make before starting. */}
-          <details className="v2-byo__more" data-testid="byo-more-ways">
+          <details className="v2-byo__more" data-testid="byo-more-ways"
+            onMouseDownCapture={(event) => {
+              if ((event.target as Element).closest('summary, button, a')) event.preventDefault();
+            }}>
             <summary>{t('agentByo.otherWays.title')}</summary>
           {machines.length === 0 && (
             <div className="v2-byo__add-computer" data-testid="byo-add-computer">