[Fix] Home page cards: add 'By:' prefix + remove unused import

[realproject7]

Problem

PR #215 missed two small items:

1. Missing "By:" prefix on writer address

Cards show the truncated address but without the "By:" label prefix that was specified in #208.

Fix: Add "By: " text before the truncated writer address in StoryCard.

2. Unused formatUnits import

src/components/StoryCardStats.tsx imports formatUnits from viem but never uses it. Only type Address is needed.

Fix: Remove unused formatUnits from the import.

Files

• src/components/StoryCard.tsx — add "By: " prefix
• src/components/StoryCardStats.tsx — remove unused import

Acceptance Criteria

• Home page cards show "By: 0xAbCd...1234" format
• No unused imports in StoryCardStats.tsx