build: adopt central Fab release pipeline

[metyatech]

Summary - Preserve the existing six migration commits and add 8d57067244aba9ca373a8b14837eedcd6250581c as the seventh normal commit. - Fix the CI checksum sidecar regex from PowerShell-expanded `r/ `n text to [\r\n], allowing ordinary r/n in filenames while rejecting actual CR/LF. - Keep the central tool pinned to de784111d9e88a3e13205494aa56ccb12a8740f3 / 0.3.1 and the Sample pin at b4c78058993e68a62fc9c16b673aec65ee668573. ## Commit history 1. build: adopt central Fab release pipeline 2. fix: normalize Git root validation for release scripts 3. fix: satisfy central Fab release validation 4. fix: add test module copyright notice 5. fix: validate packaged smoke artifact names 6. fix: support UE 5.8 packaged runtime dependencies 7. fix: validate CI artifact filenames

8. style: format runtime dependency loading ## Verification - Targeted checksum regression: 4 valid filenames accepted; 3 filenames containing CR/LF rejected. - CI workflow diff is exactly one line; trigger, self-hosted Windows runner, 10-minute timeout, pins, artifact name, upload path, checksum/report/gate checks are unchanged. - UE 5.4 Verify: Total=68 Succeeded=68 SucceededWithWarnings=0 Failed=0 NotRun=0. - UE 5.8 release: tool 0.3.1, repository head 8d57067244aba9ca373a8b14837eedcd6250581c, 12/12 gates PASS, checksum matches. - UE 5.8 Packaged Shipping Smoke: all 9 formats pass with positive geometry/material counts, material is present in IoStore, Assimp loads from the packaged runtime directory, runtime log has no DLL load failure, memory denial and compressed texture guards pass. - No product runtime API change, Sample remote unchanged, test module not included.

• clang-format gate was reproduced with the same LLVM 21.1.8 command used by Verify, then fixed.
• RuntimeAssetImport.cpp has formatting-only changes; its non-whitespace content and string literals are unchanged.
• UE 5.4 Verify: Total=68 Succeeded=68 SucceededWithWarnings=0 Failed=0 NotRun=0 on the new head.
• The exposed GitHub credential was revoked through the unauthenticated revocation endpoint; the obsolete webhook integration and its receiver were deleted instead of rotated or reused.
• No credential value is included in this PR. Self-hosted runner status is documented separately: no repository runner is registered, organization runner listing is unavailable (404), and no existing local service is safely scoped to this product repository. The old queued run for the previous head was cancelled and is not used as evidence. No Git tag or GitHub Release is included in this change.