v0.9.9 — upstream engine repin

v0.9.9 — upstream engine repin (under-the-hood)

Rebases the native chat engine (libchat) onto the latest upstream so Peers stays
current (d2124fd → 462a4884, +9 commits). No new user-facing features — the goal is
currency, stability, and groundwork. Your existing conversations carry over.

🔁 Engine / infrastructure (#427)

• Rebased the entire Peers fork onto upstream libchat main (+9 commits): #184
  delivery-based key/account publishing, #188/#189 roster + participant listing, #194
  one-step group-with-members creation, and upstream CI/build fixes.
• Re-homed our offline-contact-card feature and the GHSA-xxgx-7757-3qq6 key-package
  device-binding onto upstream's rewritten registry. The online binding is now enforced
  by upstream's own authenticated key retrieval; the offline-card path keeps our verify.
• Deferred upstream's XWING post-quantum ciphersuite flip — kept MLS_128 so this build
  stays wire- and storage-compatible with v0.9.8 (existing chats + old-version peers keep
  working). XWING will land later as a proper dual-suite migration.

✅ Verification

• 85 native (Rust) tests + 37 provenance/ABI tests + 508 app tests, all green.
• New arm64 liblogoschat.so rebuilt from the single consolidated patch (26 FFI symbols);
  fail-closed security-marker assertions pass; provenance refreshed in SBOM.md +
  SHA256SUMS. On-device runtime smoke passed (loads + runs, no crash).

Native core published by xAlisher/logos-libchat-mls-android@3c38687.