Add 11 missing MCI test fixtures (CID + SHA512 mirrors)

These 11 binary test fixtures are referenced from the
MorphologicalContourInterpolation module's test suite via .cid /
.sha512 content links but were never published to ITKTestingData.
They were authored by KitwareMedical/ITKMorphologicalContourInterpolation
and pinned only on its (now-decayed) IPFS infrastructure.  Public
IPFS gateways (dweb.link, ipfs.io, w3s.link, gateway.ipfs.io) all
return HTTP 504 Gateway Timeout for these CIDs, breaking ITK's
"Populate shared ExternalData cache" CI job on PR #6209.

Surfaced by InsightSoftwareConsortium/ITK PR #6209 (Cuberille follow-up
ingest of MCI into Modules/Filtering/MorphologicalContourInterpolation/).

Provenance and verification:
  - Source: https://data.kitware.com/api/v1/file/hashsum/sha512/<hash>/download
  - SHA512 verified: each file's downloaded bytes match the recorded
    .sha512 sidecar from the upstream MCI commit predating the
    md5/sha512 -> .cid conversion.
  - CID verified: locally computed via `npx ipfs-car pack --no-wrap`
    (UnixFS-v1-2025 / IPIP-0499 profile, matching ITK's PR #6111
    upload tooling) and confirmed equal to the `.cid` sidecar
    contents recorded in the source tree.

Files added (11 each under CID/ and SHA512/):
  c2.mha                  3.0 MB  bafkreiekrb...c37pxte
  c10.mha                 3.6 MB  bafkreic6be...67q7ie
  105769fixed.nii         31  MB  bafkreieotw...mwj64
  FaceRoIFinished.nrrd    30  KB  bafkreieh7u...phvm
  BigImage.nrrd           4.2 MB  bafkreihay3...vgxkm
  16-5-16.nrrd            1.5 KB  bafkreid5dr...cawlm
  105769moving.nii        31  MB  bafkreig2z7...pz5dq
  NDRI64816L.nii          28  MB  bafkreidgha...w2mru
  NDRI65239R.nii          28  MB  bafkreicoqr...45mpu
  GridSegBase.nrrd        1.5 KB  bafkreihnud...ctjhe
  3x3x3.nrrd              313  B  bafkreihlfu...lbua4

Total: 22 new files (11 CID + 11 SHA512), ~155 MB.

After this lands, ITK CI's PrefetchCIDContentLinks step will resolve
all 12 previously-failing MCI CIDs from the GitHub Pages mirror
(the highest-priority gateway in CMake/ITKExternalData.cmake), and
PR #6209's "Populate shared ExternalData cache" job will pass.

Author: hjmjohnson

CID/bafkreic6bek4vpsjqmbce6cnbasrs5g4o5mqoct6noo5wgdojeyp67q7ie

@@ -0,0 +1,13 @@
+NRRD0004
+# Complete NRRD file format specification at:
+# http://teem.sourceforge.net/nrrd/format.html
+type: unsigned char
+dimension: 3
+space: left-posterior-superior
+sizes: 3 3 3
+space directions: (2,0,0) (0,5,0) (0,0,3)
+kinds: domain domain domain
+encoding: raw
+space origin: (0,0,0)
+
+�2��PX7�p��u��݉����	�o