chrome.runtime.sendMessage serializes with a JSON-like algorithm that drops
ArrayBuffer/TypedArray payloads — they arrive as empty objects, so a carrier
JPEG reached the service worker as 0 bytes and failed with the opaque WASM
error "no SOF marker found in JPEG". This broke extension vault creation.
- shared/message-binary.ts: encodeBinary/decodeBinary deep-walk a message tree
and base64-envelope every binary buffer so it survives the channel (chunked
base64 to avoid stack overflow on multi-MB buffers); plain number[] untouched.
- Wire encode/decode at all four message boundaries: popup, service-worker
onMessage listener (decode request, encode response), setup swSend, vault
postToServiceWorker.
- handleCreateVault: magic-byte guard classifies empty / non-JPEG carriers into
actionable errors (carrier_image_empty / carrier_image_not_jpeg) instead of
the opaque WASM error; error-copy.ts adds user-facing text; setup errors now
route through lookupErrorCopy.
- router SETUP_ALLOWED: add create_vault / attach_vault / generate_recovery_qr —
the Phase-3 setup wizard sends these from the setup page and they were being
rejected as unauthorized_sender.
- Tests: message-binary round-trip suite (7) + carrier-guard (2) + setup
allowlist (3). 435/435 vitest, build:all clean.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pe8qw5KePDqAEBsAxnVQuJ
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