Deduplicate capability entry in docs/reference/capabilities.md

[blindzero]

Problem Statement

docs/reference/capabilities.md contains a duplicated capability entry. This is a small but visible consistency defect that can confuse users and implies missing editorial validation in documentation pages.

Proposed Solution

• Remove the duplicate capability entry.
• Ensure the final capability list is unique and consistently formatted.
• If capabilities are generated from source, fix the generator/source-of-truth instead of editing generated output manually.

Alternatives Considered

• Leaving the duplicate in place.
  • Rejected: contradicts the consistency principle and reduces documentation quality.

Impact

• Does this affect existing workflows?
  • No runtime impact.
• Any backward compatibility concerns?
  • None.

Acceptance Criteria:

• The duplicate entry is removed and the document remains valid Markdown (linting).
• If docs are generated, the duplication is fixed at the source/generator level so it cannot regress.

Additional Context

Verification:

• Run any existing docs lint/check pipeline locally or via CI.

Definition of Done:

• Doc fixed at the correct layer (source-of-truth).
• Optional: add a small docs check (unique headings/ids) only if trivial and aligned with existing tooling.