feat(host): blur cancels path editing; scrollbar clearance in the miller columns

packages/host/directory-picker-browse/src/client/DirectoryBrowser.module.css

@@ -55,7 +55,9 @@
   align-items: stretch;
   flex: 1 1 0;
   min-height: 0;
-  gap: 20px;
+  /* Columns already end in an 8px scrollbar clearance, so the divider only
+   * needs a slim gap of its own on each side. */
+  gap: 12px;
   overflow-x: auto;
   scrollbar-width: none;
 }
@@ -136,7 +138,9 @@
   flex-direction: column;
   flex: 1 1 0;
   min-height: 0;
-  padding: 16px 24px;
+  /* Right inset is slimmer than the left: the trailing column's own 8px
+   * scrollbar clearance makes up the optical difference. */
+  padding: 16px 16px 16px 24px;
 }
 
 /* Two-pane columns split the row evenly around the divider; 256px is the
@@ -149,6 +153,9 @@
   flex: 1 1 0;
   min-width: 256px;
   overflow-y: auto;
+  /* The overlay scrollbar paints at the column's edge; keep the row pills
+   * clear of the thumb. */
+  padding-right: 8px;
 }
 
 .columnWide {

packages/host/directory-picker-browse/src/client/DirectoryBrowser.tsx

@@ -200,6 +200,25 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
     })
   }, [launchListing])
 
+  /** Abandon path editing (Escape or clicking away) and restore the crumb view. */
+  const cancelPathEdit = useCallback(() => {
+    // Cancel also withdraws a navigation the editor already launched: its
+    // late success must not jump to the cancelled path, so the pending
+    // request is superseded and the view leaves the loading state.
+    supersede()
+    setLoading(false)
+    setPathDraft(null)
+    setError(null)
+    // Editing may have superseded the selection's preview request; a
+    // selection with no preview would render a half-empty two-pane view, so
+    // cancel falls back to the single-pane level.
+    if (child === null) setSelected(null)
+    // With no level listed yet (the editor superseded the initial home
+    // listing), plain cancellation would leave a permanently blank picker:
+    // restart the home listing.
+    if (parent === null) navigate()
+  }, [supersede, child, parent, navigate])
+
   /** A right-column pick advances the view one level: child becomes the level. */
   const advance = useCallback((entry: DirectoryEntry) => {
     /* v8 ignore next -- narrowing guard: the right column only renders with a child listing. */
@@ -382,25 +401,14 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
                   }
                   if (event.key === 'Escape') {
                     event.stopPropagation()
-                    // Cancel also withdraws a navigation the editor already
-                    // launched: its late success must not jump to the
-                    // cancelled path, so the pending request is superseded
-                    // and the view leaves the loading state.
-                    supersede()
-                    setLoading(false)
-                    setPathDraft(null)
-                    setError(null)
-                    // Editing may have superseded the selection's preview
-                    // request; a selection with no preview would render a
-                    // half-empty two-pane view, so cancel falls back to the
-                    // single-pane level.
-                    if (child === null) setSelected(null)
-                    // With no level listed yet (the editor superseded the
-                    // initial home listing), plain cancellation would leave a
-                    // permanently blank picker: restart the home listing.
-                    if (parent === null) navigate()
+                    cancelPathEdit()
                   }
                 }}
+                // Clicking anywhere outside the editor reads as leaving it:
+                // focus loss cancels the edit like Escape. Enter keeps focus
+                // in the input while its navigation is in flight, so a
+                // submitted path is never withdrawn by this handler.
+                onBlur={cancelPathEdit}
               />
             )}
         </div>