refactor: consolidate project loading into EntityGrid component

Unify project loading and searching logic in EntityGrid.vue to eliminate
duplication. Make entities prop optional for projects, add internal
project state, and auto-load projects when needed.

- EntityGrid: Combine search/load into fetchProjects(), add internal
  allProjects state, handle pagination internally for both search and
  load modes
- OnboardMeetingSetupView: Remove project loading methods
- MeetingProjectDialog: Remove project props
- GiftedDialog: Remove project loading logic
- EntitySelectionStep: Make projects prop optional

Reduces code duplication by ~150 lines and simplifies component APIs.
All project selection now uses EntityGrid's internal loading.

src/components/MeetingProjectDialog.vue

@@ -7,7 +7,6 @@
       <!-- EntityGrid for projects -->
       <EntityGrid
         :entity-type="'projects'"
-        :entities="allProjects"
         :active-did="activeDid"
         :all-my-dids="allMyDids"
         :all-contacts="allContacts"
@@ -16,7 +15,6 @@
         :show-unnamed-entity="false"
         :notify="notify"
         :conflict-context="'project'"
-        :load-more-callback="loadMoreCallback"
         @entity-selected="handleEntitySelected"
       />
 
@@ -58,10 +56,6 @@ export default class MeetingProjectDialog extends Vue {
   /** Whether the dialog is visible */
   visible = false;
 
-  /** Array of available projects */
-  @Prop({ required: true })
-  allProjects!: PlanData[];
-
   /** Active user's DID */
   @Prop({ required: true })
   activeDid!: string;
@@ -78,10 +72,6 @@ export default class MeetingProjectDialog extends Vue {
   @Prop()
   notify?: (notification: NotificationIface, timeout?: number) => void;
 
-  /** Callback function to load more projects from server */
-  @Prop()
-  loadMoreCallback?: (entities: PlanData[]) => Promise<void>;
-
   /**
    * Handle entity selection from EntityGrid
    * Immediately assigns the selected project and closes the dialog