Fix Enter key handling for confirmation dialogs

[OnlyYu1996]

Fixes #31.

What changed

• Use form submit handlers for wallet creation and secret-word confirmation so Enter triggers the same action as clicking the primary button.
• Let the Secret Words dialog continue on Enter and the wallet-created OK state close on Enter.
• Add Enter handling for the shared generic OK modal.
• Focus the Receive dialog OK button by default so Enter closes it without intercepting other Receive actions.

Verification

• yarn install --ignore-scripts --frozen-lockfile

px ng lint

px tsc -p tsconfig.app.json --noEmit

pm run postinstall:electron

• $env:NODE_OPTIONS='--openssl-legacy-provider'; npx ng build --configuration dev

Note: the build needs NODE_OPTIONS=--openssl-legacy-provider on Node 20 because this Angular 10 / Webpack 4 project uses legacy OpenSSL hashing. The build completed with existing CommonJS optimization warnings.