docs: refresh architecture guide for HWK Trezor stack

[cursor]

Summary

• refresh docs/architecture.md so package names and example commands match the current workspace layout
• add a source-backed HWK / Trezor architecture section covering adapter-core, the Trezor adapter, connector packages, and the lower-level session stack
• document a minimal WebUSB integration flow plus verified platform constraints for WebUSB and React Native BLE

Codepaths covered

• docs/architecture.md
• packages/hwk-adapter-core/src/index.ts
• packages/hwk-adapter-core/src/types/connector.ts
• packages/hwk-adapter-core/src/types/device.ts
• packages/hwk-adapter-core/src/types/wallet.ts
• packages/hwk-trezor-adapter/src/adapter/TrezorAdapter.ts
• packages/hwk-trezor-adapter/src/index.ts
• packages/hwk-trezor-connector/src/index.ts
• packages/hwk-trezor-connector-webusb/src/index.ts
• packages/hwk-trezor-connector-webusb/src/TrezorWebUsbConnector.ts
• packages/hwk-trezor-connector-rn-ble/src/index.ts
• packages/connect-examples/hwk-demo/hwk/src/connectorFactory.web.ts
• packages/connect-examples/hwk-demo/hwk/src/connectorFactory.native.ts
• packages/connect-examples/hwk-demo/package.json

Knowledge gaps addressed

• where the new HWK / Trezor packages fit in the repo architecture
• which public adapter methods and connector entry points are currently exposed
• what setup constraints developers must satisfy before WebUSB or RN BLE flows will work
• that packages/connect-examples/hwk-demo is still Trezor-only, so readers do not assume full multi-vendor parity yet