chore: append compat:yyjson 0.13.0

[Sunrisepeak]

Append compat:yyjson@0.13.0. Existing versions are unchanged.

Upstream: ibireme/yyjson@0.13.0 (6447536015f3d600f3d65323b10976103b337ca7).

Resources and computed SHA256:

[
  {
    "platform": "linux",
    "resources": {
      "GLOBAL": {
        "url": "https://github.com/ibireme/yyjson/archive/refs/tags/0.13.0.tar.gz",
        "size": 1641525,
        "sha256": "34e0f62a2bc11ab20d601e8ca1cc2b2079503aa45119a19133d89d19b94a0fae"
      }
    }
  },
  {
    "platform": "macosx",
    "resources": {
      "GLOBAL": {
        "url": "https://github.com/ibireme/yyjson/archive/refs/tags/0.13.0.tar.gz",
        "size": 1641525,
        "sha256": "34e0f62a2bc11ab20d601e8ca1cc2b2079503aa45119a19133d89d19b94a0fae"
      }
    }
  },
  {
    "platform": "windows",
    "resources": {
      "GLOBAL": {
        "url": "https://github.com/ibireme/yyjson/archive/refs/tags/0.13.0.tar.gz",
        "size": 1641525,
        "sha256": "34e0f62a2bc11ab20d601e8ca1cc2b2079503aa45119a19133d89d19b94a0fae"
      }
    }
  }
]

The index CI must build and resolve the candidate version before merge.

Production validation: this PR was generated by the merged tool (23c5e04948c55e606bc56ee2c649ddd4849b7ec6) from the exact plan artifact of main Action run https://github.com/mcpplibs/mcpp-index/actions/runs/39308549012 . The plan baseline is 54cad76. A repeated propose returned pending and created no second PR.

Self-review: one changed file, 10 added lines, no deletions. The new URL/SHA256 is defined once with three platform references; old 0.12.0 entries remain unchanged. All 20 executed checks passed before merge, including four exact-candidate build/run/lock checks and consumer regression.

Candidate CI: https://github.com/mcpplibs/mcpp-index/actions/runs/39308855222
Consumer CI: https://github.com/mcpplibs/mcpp-index/actions/runs/39308854904