add admin UX quick wins: nav guard, block descriptions, input labels

- rename "Providers" to "Print providers" in sidebar (#110)
- add LiveView navigation guard to EditorKeyboard hook — intercepts
  link clicks in capture phase when editor has unsaved changes (#103)
- add description field to all 26 block types, shown as subtitle in
  block picker; filter searches descriptions too (#104)
- add visible column headers (Label / Path) and proper sr-only labels
  with for attributes on nav editor inputs (#106)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/berrypod_web/components/block_editor_components.ex

@@ -416,7 +416,8 @@ defmodule BerrypodWeb.BlockEditorComponents do
     filtered =
       assigns.allowed_blocks
       |> Enum.filter(fn {_type, def} ->
-        filter == "" or String.contains?(String.downcase(def.name), filter)
+        filter == "" or String.contains?(String.downcase(def.name), filter) or
+          String.contains?(String.downcase(Map.get(def, :description, "")), filter)
       end)
       |> Enum.sort_by(fn {_type, def} -> def.name end)
 
@@ -454,7 +455,10 @@ defmodule BerrypodWeb.BlockEditorComponents do
             class="block-picker-item"
           >
             <.icon name={def.icon} class="size-5" />
-            <span>{def.name}</span>
+            <span class="block-picker-item-name">{def.name}</span>
+            <span :if={def[:description]} class="block-picker-item-desc">
+              {def.description}
+            </span>
           </button>
 
           <p :if={@filtered_blocks == []} class="block-picker-empty">

lib/berrypod_web/components/layouts/admin.html.heex

@@ -91,7 +91,7 @@
               navigate={~p"/admin/providers"}
               class={admin_nav_active?(@current_path, "/admin/providers")}
             >
-              <.icon name="hero-link" class="size-5" /> Providers
+              <.icon name="hero-link" class="size-5" /> Print providers
             </.link>
           </li>
           <li>

lib/berrypod_web/live/admin/navigation.ex

@@ -158,13 +158,19 @@ defmodule BerrypodWeb.Admin.Navigation do
       </h3>
 
       <div class="space-y-2">
+        <div :if={@items != []} class="nav-editor-labels" aria-hidden="true">
+          <span>Label</span>
+          <span>Path</span>
+        </div>
         <div
           :for={{item, idx} <- Enum.with_index(@items)}
           class="nav-editor-item"
         >
           <div class="nav-editor-fields">
+            <label class="sr-only" for={"nav-#{@section}-#{idx}-label"}>Label</label>
             <input
               type="text"
+              id={"nav-#{@section}-#{idx}-label"}
               value={item["label"]}
               placeholder="Label"
               phx-blur="update_item"
@@ -173,8 +179,10 @@ defmodule BerrypodWeb.Admin.Navigation do
               phx-value-field="label"
               class="admin-input nav-editor-input"
             />
+            <label class="sr-only" for={"nav-#{@section}-#{idx}-href"}>Path</label>
             <input
               type="text"
+              id={"nav-#{@section}-#{idx}-href"}
               value={item["href"]}
               placeholder="/path"
               phx-blur="update_item"