Validate and sanitize Stellar explorer and external links to prevent open-redirect/tabnabbing

[1nonlypiece]

📌 Description

Components like src/components/dashboard/CommitmentDetailNftSection.tsx
(onViewOnExplorer, ExternalLink) and NFT/marketplace views build outbound
links to a Stellar explorer using contract/token/owner identifiers. Outbound
links opened in a new tab without rel="noopener noreferrer", and explorer URLs
constructed from unvalidated identifiers, expose the app to reverse tabnabbing
and malformed/redirecting URLs.

This issue centralizes explorer/external link construction and hardens it.

Goal: all external links are built through a validated helper that enforces
an allowlisted explorer base and safe rel/target attributes.

🎯 Requirements and Context

• Add a buildExplorerUrl(kind, id) helper that validates id shape (Stellar
  address / tx hash / token id) and only emits URLs against an allowlisted
  explorer base from config.
• Ensure all target="_blank" links use rel="noopener noreferrer".
• Reject or safely encode unexpected identifier input.
• Apply across NFT section, NFT display, marketplace, and commitment detail.
• Align with docs/backend-security-checklist.md / backend-threat-model.md
  where relevant.

🛠️ Suggested Execution

1. Create a branch

git checkout -b feature/safe-external-links

2. Implement changes

• Add src/utils/explorerLinks.ts with buildExplorerUrl + validation.
• Replace ad-hoc link construction in the components above.
• Add src/utils/__tests__/explorerLinks.test.ts.

3. Test and commit

• Run npm test.
• Edge cases: malformed id, injection attempt in id, missing explorer config,
  unknown link kind.

Example commit message

fix: validated explorer link helper and safe rel/target on external links

✅ Guidelines

• Minimum 95% test coverage on the link helper.
• Clear documentation of allowlist and validation rules.
• Timeframe: 96 hours.

🏷️ Labels

type-security · area-frontend · MAYBE REWARDED · GRANTFOX OSS · OFFICIAL CAMPAIGN

💬 Community & Support

• Join the CommitLabs contributor Discord: https://discord.gg/WV7tdYkJk
• Introduce yourself before starting to avoid duplicate work.
• Maintainers triage actively and review fast.