fix(storage): normalize custom gatewayUrl in IPFSStorage.upload (#504)

[aazminu]

Pull Request

Description

Factors gateway URL normalization (replace(/\/+$/, '') + ensuring the /ipfs path segment) out of IPFSStorage.resolve() into shared helpers (normalizeGatewayUrl and buildGatewayCidUrl) and uses buildGatewayCidUrl in IPFSStorage.upload(). This ensures upload() returns the exact same gateway URL that resolve() requests when a custom gatewayUrl is configured without an /ipfs suffix or with trailing slashes.

Linked Issue

Closes #504

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change — see docs/VERSIONING.md; add a ### ⚠️ Breaking Changes changelog entry and a docs/UPGRADING.md section)
• Documentation update
• Dependency update
• Refactor (no functional changes)

Checklist

Code Quality

• TypeScript strict mode: no any types in public APIs
• All public functions have JSDoc comments
• Code follows the project's style (run npm run format:check to verify)
• Linting passes: npm run lint
• Type checking passes: npm run typecheck (and npm run typecheck:tests if tests were modified)

Testing

• Tests added or updated for new/changed functionality
• Tests pass: npm run test
• Test coverage maintained or improved (run npm run test:coverage to check)
• No unrelated test changes

Documentation

• CHANGELOG.md updated with entry under [Unreleased] section, formatted as:

  - Issue #504: Factored gateway URL normalization out of `IPFSStorage.resolve` into a shared helper used by both `upload()` and `resolve()` so custom gateways without an `/ipfs` suffix return consistent gateway URLs.

• README updated if user-facing features changed
• API documentation (docs/API.md) updated if public API changed
• Architecture documentation (docs/ARCHITECTURE.md) updated if module structure/patterns changed
• JSDoc comments are clear and include examples for complex functions

General

• No console.log() or debug code left behind
• No unrelated files committed
• Branch follows convention: fix/[issue-number] or feature/[description]
• Commit messages are descriptive and reference issue numbers where applicable

Notes

Verified with npx jest tests/storage.test.ts tests/storage-resolve.test.ts, npm run typecheck, npm run lint, and npx prettier --check.