[boburning]

Summary

• add the transport-neutral bloom-sync transaction engine for authenticated Ed25519 save bundles
• enforce bounded canonical manifests, immutable bundle IDs, peer key/epoch trust, ordered compatibility/conflict classification, quarantine, and explicit resolution
• publish only verified whole-save snapshots with same-directory atomic replacement and rollback of both live bytes and lineage state on late failure
• expose the bounded bloomctl sync grammar and make bloom-network-sync status report engine readiness without starting transport or listeners
• package the sync contract/schema, refresh provenance inventories, and document the architecture/security boundary
• route the shipped OpenSSL through BloomOS-owned runtime libraries; this was discovered and regression-tested with a read-only Mini Plus capability probe
• make the RetroArch identity regression test mutate current legacy inventory totals structurally instead of hard-coding a stale generated snapshot
• record SYNC-02 as device-gate pending in the authoritative v3 ledger while leaving SYNC-03 and SYNC-04 planned

This slice deliberately provides no cloud/provider/transport implementation and opens no network listener.

Verification

• native test suite: 595/595
• AddressSanitizer suite: 595/595
• full shell matrix: 850/850 across 8 shards
• focused sync/network/provenance/FAT suite: 47/47
• focused bloom-sync and ledger suite: 19/19
• UI gallery: 10/10, byte-identical goldens and 0 changed pixels
• full cppcheck: exit 0 (existing warnings only)
• clean pinned local ARM cross-build on runtime commit 8077e94481c202a93f64d512a05bbf7c85384952: all primary and external owners completed; ci-build [READY!]
• Linux RetroArch identity regression suite on test-only head 9ce3b5ddb148382f39ac15fc4d9e0b0963248574: 3/3
• hosted exact-head checks on a9fd690627738985a016cb7df824574d6de14b4c: native, AddressSanitizer, 850-test shell, static analysis, and clean ARM all passed
• current Mini Plus read-only capability probe: Ed25519 public DER 44 bytes, signature 64 bytes, canonical jq sorting passed, runtime-owned OpenSSL library scope passed, temporary probe scope cleaned

Device gate

Risk 3 / Warm. No SYNC-02 candidate was deployed. The signed UI-12 candidate from #644 remains the sole installed testing candidate and still needs the user's physical observation of normal shutdown text and actual power-off. After that gate, this PR still requires its own signed Mini Plus candidate deployment, structured health/feature evidence, cleanup, rollback verification, and any required physical validation before merge.

Closes #650