fix(web): align the directory browser with the figma frame and merge the seam tip

The dialog now owns the figma structure through a new headless Modal
mode (mask/card/Escape stay shared): header block with the title and
crumbs 8px apart above the l3 separator (no close chrome — the figma
frame has none), 16px to the level, and the 12px card bottom. The
picker-kind narrowing returns for the merged open describe kind — an
unrecognized advertised kind hides the local-folder entry, now covered
alongside the stale-navigation failure arm and the unmount races.

packages/client/ui-primitives/src/Modal.tsx

@@ -12,13 +12,16 @@ import css from './Modal.module.css'
  * Render a centered modal over a blurred page mask.
  * @param props.open - whether the dialog is showing.
  * @param props.onClose - Escape or mask click.
- * @param props.title - dialog heading.
+ * @param props.title - dialog heading (aria-label in every mode).
  * @param props.description - optional supporting sentence under the title.
  * @param props.children - body (inputs, etc.).
  * @param props.footer - action row (Cancel / Create).
+ * @param props.headless - render children directly in the card (no default
+ * header/close/body chrome) for dialogs whose figma frame owns its own
+ * header structure; mask, card, Escape, and aria-label remain.
  * @returns null when closed; otherwise the overlay tree.
  */
-export function Modal({ open, onClose, title, description, children, footer, className }: {
+export function Modal({ open, onClose, title, description, children, footer, className, headless = false }: {
   open: boolean
   onClose: () => void
   title: string
@@ -26,6 +29,7 @@ export function Modal({ open, onClose, title, description, children, footer, cla
   children?: ReactNode
   footer?: ReactNode
   className?: string
+  headless?: boolean
 }) {
   useEffect(() => {
     if (!open) return
@@ -47,19 +51,25 @@ export function Modal({ open, onClose, title, description, children, footer, cla
         aria-modal="true"
         aria-label={title}
       >
-        <div className={css.content}>
-          <div className={css.header}>
-            <h2 className={css.title}>{title}</h2>
-            <button type="button" className={css.close} aria-label="Close" onClick={onClose}>
-              <IconCloseOutline16 size={14} />
-            </button>
-          </div>
-          {description !== undefined && description !== '' && (
-            <p className={css.description}>{description}</p>
+        {headless
+          ? children
+          : (
+            <>
+              <div className={css.content}>
+                <div className={css.header}>
+                  <h2 className={css.title}>{title}</h2>
+                  <button type="button" className={css.close} aria-label="Close" onClick={onClose}>
+                    <IconCloseOutline16 size={14} />
+                  </button>
+                </div>
+                {description !== undefined && description !== '' && (
+                  <p className={css.description}>{description}</p>
+                )}
+                {children !== undefined && <div className={css.body}>{children}</div>}
+              </div>
+              {footer !== undefined && <div className={css.footer}>{footer}</div>}
+            </>
           )}
-          {children !== undefined && <div className={css.body}>{children}</div>}
-        </div>
-        {footer !== undefined && <div className={css.footer}>{footer}</div>}
       </div>
     </div>
   )