feat(directory): add option to hide owner card in user directory

Add HIDE_OWNER_CARD environment variable to optionally hide the directory owner's card. Update UserDirectory component to display owner DID in no-users message and pass primaryUserDid prop for filtering.

.env.example

···
 # Primary user DID (required if no users configured)
 DIRECTORY_OWNER=did:plc:your-did-here
 
+# Hide the directory owner's card (optional, default: false)
+HIDE_OWNER_CARD=false
+
 # Multiple users (comma-separated, optional)
 # These users will be displayed alongside DIRECTORY_OWNER
 PUBLIC_LINKAT_USERS=did:plc:user1,did:web:user2,did:plc:user3

README.md

···
     PUBLIC_LINKAT_USERS=did:plc:user1,did:web:user2
     ```
 
+    Example for hiding the directory owner's card:
+    ```
+    HIDE_OWNER_CARD=true
+    ```
+
 4.  **Run the development server:**
     ```bash
     npm run dev

src/lib/components/archive/UserDirectory.svelte

···
   import type { User } from "$lib/components/shared/interfaces";
 
   export let users: User[];
+  export let primaryUserDid: string | undefined;
 
   let loading = true;
   let userProfiles: any[] = [];
···
     </div>
   {:else if userProfiles.length === 0}
     <div class="text-center py-8">
-      <p class="text-lg opacity-75">No users configured. Add users in the configuration file.</p>
+      <p class="text-lg opacity-75">
+        No users configured or found. Please check your configuration and ensure users have associated Linkat data. 
+        {#if primaryUserDid}
+          <br />Directory owner is set to: {primaryUserDid}
+        {:else}
+          <br />No directory owner is set.
+        {/if}
+      </p>
     </div>
   {:else}
     <div class="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6">

src/routes/+layout.ts

···
     posts: new Map(),
     dynamicLinks,
     userLinkBoards,
-    linkatUsers: userDids,
+    linkatUsers: userDids.filter(did => {
+      const hideOwnerCard = env.HIDE_OWNER_CARD === 'true';
+      if (hideOwnerCard && did === primaryUserDid) {
+        return false; // Hide the owner's card if HIDE_OWNER_CARD is true
+      }
+      return userLinkBoards[did] !== undefined;
+    }),
     noUsersConfigured: false,
+    primaryUserDid,
   };
 }

src/routes/+page.svelte

···
       </div>
     </div>
   {:else}
-    <UserDirectory users={data.linkatUsers.map(did => ({ did }))} />
+    <UserDirectory users={data.linkatUsers.map(did => ({ did }))} primaryUserDid={data.primaryUserDid} />
   {/if}
 </div>