feat(FN-2493): add plugin add alias and normalize install guidance

- Route "fn plugin add" to the plugin install handler and update CLI help/usage text to document the alias
- Add bin routing tests that cover plugin add/install parity and updated error/help messaging
- Update getting-started, settings reference, and runtime plugin READMEs to standardize plugin installation examples
- Add a patch changeset for @runfusion/fusion and apply DirectoryPicker/PluginManager design-token styling refinements

packages/dashboard/app/components/DirectoryPicker.css

@@ -16,34 +16,8 @@
 }
 
 .directory-picker-browse-btn {
-  display: inline-flex;
-  align-items: center;
-  gap: 6px;
-  padding: 8px 14px;
-  background: var(--surface);
-  border: 1px solid var(--border);
-  border-radius: var(--radius-md);
-  color: var(--text);
-  font-size: 13px;
-  cursor: pointer;
+  flex-shrink: 0;
   white-space: nowrap;
-  transition:
-    background-color var(--transition-fast),
-    border-color var(--transition-fast);
-}
-
-.directory-picker-browse-btn:hover {
-  background: var(--card-hover);
-  border-color: var(--text-dim);
-}
-
-.directory-picker-browse-btn:focus-visible {
-  outline: none;
-  box-shadow: var(--focus-ring-strong);
-}
-
-.directory-picker-browse-btn:active {
-  transform: scale(0.97);
 }
 
 .directory-picker-browser {
@@ -59,22 +33,20 @@
 .directory-picker-breadcrumbs {
   display: flex;
   align-items: center;
-  gap: 2px;
+  gap: var(--space-xs);
   padding: var(--space-sm) var(--space-md);
   background: var(--surface);
   border-bottom: 1px solid var(--border);
   overflow-x: auto;
   white-space: nowrap;
-  font-size: 12px;
 }
 
 .directory-picker-breadcrumb {
   background: none;
   border: none;
-  padding: 2px 4px;
+  padding: var(--space-xs);
   border-radius: var(--radius-sm);
   color: var(--todo);
-  font-size: 12px;
   cursor: pointer;
   font-family: var(--font-mono);
 }
@@ -84,6 +56,11 @@
   text-decoration: underline;
 }
 
+.directory-picker-breadcrumb:focus-visible {
+  outline: none;
+  box-shadow: var(--focus-ring-strong);
+}
+
 .directory-picker-breadcrumb-item {
   display: inline-flex;
   align-items: center;
@@ -104,28 +81,22 @@
 
 .directory-picker-up-btn,
 .directory-picker-hidden-toggle {
-  display: inline-flex;
-  align-items: center;
-  gap: var(--space-xs);
-  padding: var(--space-xs) var(--space-sm);
-  background: none;
-  border: 1px solid transparent;
-  border-radius: var(--radius-sm);
   color: var(--text-muted);
-  font-size: 11px;
-  cursor: pointer;
-  transition: all var(--transition-fast);
 }
 
 .directory-picker-up-btn:hover,
 .directory-picker-hidden-toggle:hover {
-  background: var(--surface);
-  border-color: var(--border);
   color: var(--text);
 }
 
+.directory-picker-up-btn:focus-visible,
+.directory-picker-hidden-toggle:focus-visible {
+  outline: none;
+  box-shadow: var(--focus-ring-strong);
+}
+
 .directory-picker-entries {
-  max-height: 240px;
+  max-height: calc(var(--space-2xl) * 8);
   overflow-y: auto;
   padding: var(--space-xs) 0;
 }
@@ -135,11 +106,10 @@
   align-items: center;
   gap: var(--space-sm);
   width: 100%;
-  padding: 6px var(--space-md);
+  padding: var(--space-xs) var(--space-md);
   background: none;
   border: none;
   color: var(--text);
-  font-size: 13px;
   cursor: pointer;
   text-align: left;
   transition: background-color var(--transition-fast);
@@ -149,6 +119,11 @@
   background: var(--card-hover);
 }
 
+.directory-picker-entry:focus-visible {
+  outline: none;
+  box-shadow: var(--focus-ring-strong);
+}
+
 .directory-picker-entry-icon {
   color: var(--todo);
   flex-shrink: 0;
@@ -175,7 +150,6 @@
   gap: var(--space-sm);
   padding: var(--space-xl);
   color: var(--text-muted);
-  font-size: 13px;
 }
 
 .directory-picker-error {
@@ -184,11 +158,10 @@
   gap: var(--space-sm);
   padding: var(--space-md);
   margin: var(--space-sm) var(--space-md);
-  background: rgba(248, 81, 73, 0.1);
-  border: 1px solid var(--error);
+  background: color-mix(in srgb, var(--color-error) 10%, transparent);
+  border: 1px solid var(--color-error);
   border-radius: var(--radius-md);
-  color: var(--error);
-  font-size: 13px;
+  color: var(--color-error);
 }
 
 .directory-picker-actions {
@@ -207,7 +180,6 @@
   overflow: hidden;
   text-overflow: ellipsis;
   white-space: nowrap;
-  font-size: 12px;
   font-family: var(--font-mono);
   color: var(--text-muted);
 }