fix: keep RHF bounty USD display at $150

[2bf]

Summary

• make Foundation bounty detection resilient when NEXT_PUBLIC_FOUNDATION_USER_ID is unavailable
• fall back to the public ResearchHub Foundation account name across the bounty API shapes already handled by bountyUtil
• lets existing work header, bounty tab, banner, and bounty card display helpers keep RHF peer-review bounties at the flat $150 USD amount

Closes ResearchHub/issues#355

Testing

• git diff --check
• attempted npm ci, but install is blocked by private Tiptap registry credentials: 403 Forbidden - https://registry.tiptap.dev/@tiptap-pro/extension-unique-id/...
• attempted npx -p typescript@5.9.3 tsc --noEmit -p tsconfig.json --pretty false, but it fails after the blocked install because project dependencies/types are missing

[vercel]

@2bf is attempting to deploy a commit to the ResearchHub Team on Vercel.

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[chatgpt-codex-connector]

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[2bf]

Updated the branch to address the SonarCloud S7765 hint. SonarCloud now reports 0 open new issues for this PR; git diff --check is clean locally. I could not run npm run type-check in this checkout because dependencies are not installed (tsc: command not found).