refactor(web): reuse the shared address formatter in the round hook

[karagozemin]

Problem

The round-session hook contains a private shortAddr implementation identical to the shared web formatting helper. This duplicate can drift from the formatter used elsewhere in the UI.

Task

Import and use the shared formatter, then remove the local duplicate.

Acceptance criteria

• The hook uses the shared address formatter.
• Displayed output remains unchanged.
• Web tests and typecheck pass.
• No unrelated hook logic changes.

Suggested implementation prompt

Replace the round-session hook local address formatter with the existing shared helper, remove the duplicate function, run web tests and typecheck, and keep the diff focused.

[emrekayat]

can ı work on it?

[grantfox-oss]

🦊 GrantFox — @emrekayat has been assigned to this issue as part of the Third Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #258)
2. Your PR will be reviewed by the Sub-Rosa-Issue maintainers

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