Implement ETH send and QR code receive

Send: stores mnemonic/private key with wallet data, derives
signing key from mnemonic + address index via ethers HDNodeWallet,
constructs transaction with parseEther, broadcasts via
sendTransaction, waits for confirmation, shows block number
and tx hash. ENS resolution in To field preserved.

Receive: QR code rendered to canvas via qrcode library (1.5.4).
Shows scannable QR above the full address text.

README updated with qrcode dependency and TODO progress.

README.md

@@ -332,6 +332,7 @@ delegated to these libraries — see the Crypto Policy section below.
 | ------------------------- | ------- | ------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
 | `ethers`                  | 6.16.0  | MIT     | All Ethereum operations: BIP-39 mnemonic generation/validation, BIP-32/BIP-44 HD key derivation (`m/44'/60'/0'/0/n`), secp256k1 signing, transaction construction, ERC-20 contract interaction, JSON-RPC communication, address derivation (keccak256). |
 | `libsodium-wrappers-sumo` | 0.8.2   | ISC     | Password-based encryption of secrets at rest: Argon2id key derivation (`crypto_pwhash`), authenticated encryption (`crypto_secretbox` / XSalsa20-Poly1305).                                                                                             |
+| `qrcode`                  | 1.5.4   | MIT     | QR code generation for the Receive screen (renders address as scannable QR on canvas).                                                                                                                                                                  |
 
 Dev dependencies (not shipped in extension):
 
@@ -478,14 +479,14 @@ Everything needed for a minimal working wallet that can send and receive ETH.
 - [ ] Encrypt recovery phrase / private key with password via libsodium
       (Argon2id + XSalsa20-Poly1305)
 - [ ] Password prompt on Send (decrypt private key to construct transaction)
-- [ ] Transaction construction via ethers.js (to, value, gasLimit, gasPrice)
+- [x] Transaction construction via ethers.js (to, value, gasLimit, gasPrice)
 - [ ] Gas estimation and fee display before confirming
-- [ ] Broadcast transaction via `eth_sendRawTransaction`
-- [ ] Transaction status feedback (pending → confirmed / failed)
+- [x] Broadcast transaction via `eth_sendRawTransaction`
+- [x] Transaction status feedback (pending → confirmed / failed)
 
 ### Receiving
 
-- [ ] QR code generation for address (text-based or lightweight QR library)
+- [x] QR code generation for address (qrcode library, renders to canvas)
 
 ### Display