fix(client): hide OpenDisputeForm when a dispute is already Open

[shinzoxD]

Summary

OpenDisputeForm no longer offers a second open-dispute action when the campaign already has an open dispute.

The form now calls useDispute(campaignId) and, when status.tag === 'Open', replaces the reason field and submit button with a short status message so users are not asked to sign a duplicate open_dispute that the contract will reject (campaign not disputable).

Closes #188

Changes

• OpenDisputeForm checks useDispute() and hides the form when a dispute is already Open
• Eligible wallets see: "A dispute is already open on this campaign — an admin needs to resolve it before a new one can be opened."
• Wired the form into CampaignDetailPage so the guard is reachable from the campaign UI

Tests

• New test in client/src/components/campaign/__tests__/OpenDisputeForm.test.tsx: given a mocked open dispute, the form (reason field + submit) does not render and the explanatory message does
• Existing eligibility / submit / error tests still pass (8/8 in this file)

cd client && npx eslint src/components/campaign/OpenDisputeForm.tsx src/components/campaign/__tests__/OpenDisputeForm.test.tsx
cd client && npx vitest run src/components/campaign/__tests__/OpenDisputeForm.test.tsx

Repo-wide npm run lint still reports pre-existing Windows prettier/prettier Delete ␍ errors on untouched files (same as master with core.autocrlf=true). The new files lint clean.

Payout wallet

GBVHELLD2JE235Y2NGTDT3MWI3T65ON6SY4N6FBHYVDAQ5FZC2CP5QXH

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[shinzoxD]

Closing as overlapping with #183 (@LamsOfJos), which already adds OpenDisputeForm for #145.

#188 (duplicate-open guard) should land on top of that form after #183 merges, not as a second copy of the component.