Fixes a TS2345 that npx tsc --noEmit missed (it cannot resolve the generated
wasm/relicario_wasm types, degrading SessionHandle) but the webpack build
catches with real types: session.setCurrent(handle) was passed a
SessionHandle|null. Capture the unlock result in a non-null `const h:
SessionHandle` for the in-scope ops; `handle` remains the ownership tracker
the finally block cleans up.
Simplify pass: extract the shared register_device + addDevice + persist-config
tail into registerDeviceAndPersistConfig (both handlers ended identically),
hoist the Argon2 params literal to DEFAULT_PARAMS_JSON, and fan out the two
independent read-only GETs in the attach path via Promise.all.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>