Register mirror: HORIZON SHIELD (ogasurfproject-jpg/trace-registry-mirror)

[ogasurfproject-jpg]

Registers a second independent mirror, following docs/mirroring.md.

• Operator: HORIZON SHIELD, The HORIZONs Co., Ltd. (Japan). No relationship with OPAQUE Systems or AgenTrust.
• Mirror: https://github.com/ogasurfproject-jpg/trace-registry-mirror, mirrored branch main, head at https://api.github.com/repos/ogasurfproject-jpg/trace-registry-mirror/commits/main. main carries no commit of ours and follows canonical by fast-forward only (at 221af17a345f when this was written).
• Sync: scheduled for :17 and :47 from the mirror-ops default branch, with the merge-base --is-ancestor gate from the recipe. GitHub runs schedules best effort, so in practice the mirror catches up every few hours, not every half hour. On a refusal the mirror stays where it was and the run fails. Pushes use a deploy key scoped to the mirror repository. A deploy-key push starts canonical's own push workflows on main, so the job switches them off before each push, and after it switches off any workflow file the new commit brought and cancels any run the push started. One run of each did start once, on 2026-10-04, before the second half was in place.
• Security contact: contact@the-horizons-innovation.com, published in https://shield.the-horizons-innovation.com/.well-known/security.txt (RFC 9116), policy at https://shield.the-horizons-innovation.com/security/.
• Commitment: at least 12 months from registration, or we remove the entry.

One addition beyond the recipe, in case it helps with the witness time item in ROADMAP.md: on each new head, and once a day otherwise, the mirror writes a canonical JSON record of what it observed (canonical head, our head, every registry NDJSON file at that head with its SHA-256, and each line's Merkle root and MMR checkpoint, copied and not re-verified) and stamps it with OpenTimestamps. The first record, witness/heads/2026/10/20261003T144635Z_0248406c5862.json on mirror-ops, is anchored in Bitcoin block 969745. That fixes the observed head and checkpoint roots in time by a clock neither of us controls. It does not verify any signature, and it does not show that every observer saw the same history. Happy to change or drop it if it gets in the way.