intl: realign manifests for roadmap consolidation

PR #18775 moved roadmap content but left the centralized .manifests/ tree untouched, which would make the pipeline treat the moved quantum-resistance page as brand-new and full-retranslate all 24 locales. Mirror the content ops in the manifests: rename the 24 quantum-resistance translation manifests from roadmap/future-proofing/ to roadmap/security/ (repointing sourceFile) and delete the 24 future-proofing page manifests.

sourceCommitSha is intentionally left stale here; a follow-up stamp_only run re-stamps these at the new path so the pipeline sees them in sync instead of forcing a full re-translation.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Co-Authored-By: wackerow <54227730+wackerow@users.noreply.github.com>

Author: 3 people

.manifests/public/content/translations/ar/roadmap/future-proofing/index.md/source.json

@@ -1,6 +1,6 @@
 {
   "version": 1,
-  "sourceFile": "public/content/roadmap/future-proofing/quantum-resistance/index.md",
+  "sourceFile": "public/content/roadmap/security/quantum-resistance/index.md",
   "generatedAt": "2026-04-24T21:55:31.948Z",
   "rootHash": "0c3d75173ec0",
   "tree": {