feat(client): declutter space sidebar and global header

- Remove the large active-space name header in the space sidebar;
  the active space stays highlighted in the spaces grid below.
- Move "Space settings" into the user avatar (top) menu next to
  "Workspace settings"; it shows only while viewing a space and is
  detected via useMatch("/s/:spaceSlug/*").
- Make the brand logo non-selectable/non-draggable (user-select:none
  on .brand, draggable=false on the img).
- Remove the redundant "Home" button next to the logo (the logo
  already links to /home).
- Remove the version label under the Settings sidebar menu.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

apps/client/src/components/layouts/global/app-header.module.css

@@ -13,6 +13,7 @@
     text-decoration: none;
     color: inherit;
     cursor: pointer;
+    user-select: none;
 }
 
 .brandIcon {
@@ -33,21 +34,3 @@
        that is ~9.3px, minus the font descent (~2px) ≈ 7px. */
     margin-bottom: rem(7px);
 }
-
-.link {
-    display: block;
-    line-height: 1;
-    padding: rem(8px) rem(12px);
-    border-radius: var(--mantine-radius-sm);
-    text-decoration: none;
-    color: light-dark(var(--mantine-color-gray-7), var(--mantine-color-dark-0));
-    font-size: var(--mantine-font-size-sm);
-    font-weight: 500;
-    user-select: none;
-    white-space: nowrap;
-    flex-shrink: 0;
-
-    @mixin hover {
-        background-color: light-dark(var(--mantine-color-gray-0), var(--mantine-color-dark-6));
-    }
-}