refactor: pass full draft data instead of re-fetching

The useLoadDraft and useDeleteDraftMutation hooks were fetching drafts
via getDrafts() to look up a draft by ID. This was problematic because
getDrafts is paginated, so drafts not on the first page wouldn't be
found.

Changes:
- Add full Draft object to DraftSummary type
- useLoadDraft now takes Draft directly (only loads local media)
- useDeleteDraftMutation now takes {draftId, draft} to avoid re-fetch
- Update DraftItem and DraftsListDialog to pass full draft data

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/view/com/composer/drafts/state/api.ts

@@ -289,12 +289,12 @@ export function draftViewToSummary(
 
   return {
     id: view.id,
+    draft: view.draft,
     previewText,
     hasMedia,
     hasMissingMedia,
     mediaCount,
     postCount: view.draft.posts.length,
-    isReply: false, // Reply drafts not supported
     updatedAt: view.updatedAt,
     posts,
   }