Implement reusable knockout spider component in DCAR

[petternitter]

Summary

The purpose of this issue is to build a reusable knockout spider component in DCAR that can support major tournament knockout structures without requiring us to revive and adapt the existing bespoke implementation every time.

This issue is focussed on the frontend component and the data/configuration pipeline it needs. It covers the "plumbing" needed for future editorial configurability, but not the tooling work itself.

Note: We should ensure the existing component has been through a design review prior to picking up this issue.

Why

Currently, we rely on an existing knockout spider implementation that needs to manually be revived / modified and tested ahead of major tournaments. We want to remove this repeated engineering overhead and give editorial colleagues the tools they need to cover major tournaments without having a dependency on engineering.

For World Cup 2026, we pragmatically decided to revive the existing implementation to ensure we have something ready for kick-off. But longer term, we want to move the spider into DCAR as a reusable, editorially configurable component.

The next step is therefore to build the DCAR component with a clear data/configurability architecture, so that tooling integration can be added later by appropriately resourced teams/missions.

Scope

Implement a reusable knockout spider frontend component in DCAR that can:

• Support knockout-style structures
• Render different numbers of stages and fixtures
• Handle pre-tournament placeholder teams, confirmed teams, scores, match status and match comments
• Work across our supported breakpoints
• Act as a foundation / contract for data / configuration that editorial tooling can integrate with
• Document any assumptions / limits related to editorial configurability

The implementation should separate:

• The frontend presentation of the component
• The data/configuration shape it consumes
• Any future editorial tooling needed to manage / configure the component

Out of scope

• Implementing configurability via editorial tooling
• Changes to Composer / other editorial systems
• A full tournament/bracket tool
• Speculative tournament formats without a clear need / editorial intent
• Configuration by editorial users (for this phase)

Deliverable

A reusable knockout spider component built in DCAR, with a documented data/configuration foundation that can later be wired into our editorial tooling.

Acceptance criteria

• A reusable knockout spider frontend component exists in DCAR
• The component can support knockout-style structures
• The component is not tightly coupled to a single tournament structure / length
• The component consumes a clear and documented data / configuration shape
• The component includes the frontend plumbing needed for future tooling integration where possible / based on assumptions
• The component renders as expected across different breakpoints
• Assumptions / limitations are documented
• Expected / assumed future tooling work is clearly documented but not implemented as part of this issue