Add cursor pagination to the config listing endpoint

[mikewheeleer]

Paginate the config listing

Description

The config listing endpoint returns an unbounded array, which does not scale as data grows. This issue adds cursor-based pagination with a bounded page size.

Requirements and context

• Repository scope: StableRoute-Org/Stableroute-backend only.
• Add opaque-cursor pagination (bounded default + max page size) to the config listing.
• Return a stable next-cursor; keep existing filters working across pages.
• Do not change the item shape.

Suggested execution

• Fork the repo and create a branch
• git checkout -b feature/config-01-pagination
• Implement changes
  • Write code in: the relevant module.
  • Write comprehensive tests in: cover the new behaviour and edge cases.
• Test and commit

Test and commit

• Run npm run lint, npm test, and npm run build.
• Cover edge cases: empty set, exact-page boundary, over-limit clamp, invalid cursor.
• Include the full test output in the PR description.

Example commit message

feat(config): add cursor pagination

Guidelines

• Minimum 95 percent test coverage for impacted modules.
• Clear, reviewer-focused documentation.
• Timeframe: 96 hours.

Community & contribution rewards

• 💬 Join the StableRoute community on Discord: https://discord.gg/37aCpusvx
• ⭐ This is a GrantFox OSS / Official Campaign task and may be rewarded. When your PR is merged you'll be prompted to rate the project — a 5-star rating is much appreciated.