Replaces destroy-then-rebuild Noise re-handshakes with an atomic reconnect protocol: prepared XX message-1 handoff tokens (claim-once, invalidated by crossed inbound initiations), receive-only quarantine of the established transport while an inbound replacement proves identity (promote on success, rollback+cooldown on failure/timeout), deterministic lower-peerID-wins crossed-initiator resolution, and a per-link-epoch BLE revalidation policy that re-proves cached sessions inside the same bleQueue critical section as the link rebind. On main, a fresh msg1 simply destroys an established session and rekey spans two non-atomic barriers.
Includes the review fix: timeout-restores defer outbound queue draining until the convergence retry completes (restore reason plumbed end-to-end), so DMs are never drained under keys a restarted peer already discarded — with a deterministic interleaving test. Identity-mismatch restores drain immediately. Full local suite 1768 tests green.
Closes the last cleartext private-content path over BLE: private DM images/voice were sent as plaintext signed fileTransfer packets, TTL-relayed across the mesh, so every relay saw the full bytes. Now the complete BitchatFilePacket is encrypted as a single Noise AEAD message (inner type 0x20, matching Android) and the opaque ciphertext is fragmented. Adds an authenticated in-session capability proof (0x21 TLV: capabilities + Ed25519 key), TOFU-style downgrade pinning, a per-send consent dialog for the signed-cleartext fallback to legacy peers, and a cancellation/admission registry so cancel/delete cannot race a deferred cleartext send.
Android wire constants (0x20 / 0x21 / capability bit 8) confirmed shipping. The 256-fragment preflight cap applies only to the directed fileTransfer migration fallback; encrypted media to capable peers uses the full receiver ceiling.
Rebased over #1428/#1349: identity reads go through BLELocalIdentityStateStore; the session-bound authenticated signing-key check and the announce-path TOFU pin are kept as complementary checks. Full local suite green (1744+197 tests).
Announces now carry an optional capabilities TLV (0x05): a little-endian
bitfield with named bits for upcoming features (prekeys, wifiBulk,
gateway, groups, board, vouch, meshDiagnostics). Old clients skip the
unknown TLV; peers without it decode as nil so features can distinguish
"legacy peer" from "advertises nothing".
PeerCapabilities lives in BitFoundation with a minimal-length encoding
that preserves unknown bits for forward compatibility. Peer capabilities
are stored in the BLE peer registry on verified announce and exposed via
BLEService.peerCapabilities(_:). The local advertisement set is empty
until each feature ships its bit.
Co-authored-by: jack <jackjackbits@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
