Review technical content: Desktop Wallet shared accounts - transactions

Technical review of the multi-signature transaction features under "Shared accounts with multiple credentials in Desktop Wallet" to verify technical accuracy and completeness.

Review focus:

* Correctness of all technical information
* Completeness of information
* Removal of irrelevant or redundant information

Review is complete when:

* All technical information has been verified
* Missing information has been identified and added
* Irrelevant or redundant information has been deleted
* PR with necessary changes has been submitted

Pages to review:

1. [Create a multi-signature CCD transfer in the Desktop Wallet](https://docs.concordium.com/en/mainnet/docs/desktop-wallet/multisig-simple-transfer.html): [https://github.com/Concordium/concordium.github.io/blob/main/source/mainnet/docs/desktop-wallet/multisig-simple-transfer.rst](https://github.com/Concordium/concordium.github.io/blob/main/source/mainnet/docs/desktop-wallet/multisig-simple-transfer.rst)
2. [Create a scheduled transfer in the Desktop Wallet](https://docs.concordium.com/en/mainnet/docs/guides/multisig-transfer.html): [https://github.com/Concordium/concordium.github.io/blob/main/source/mainnet/docs/guides/multisig-transfer.rst](https://github.com/Concordium/concordium.github.io/blob/main/source/mainnet/docs/guides/multisig-transfer.rst)
3. [Sign a transaction proposal](https://docs.concordium.com/en/mainnet/docs/desktop-wallet/sign-transaction.html): [https://github.com/Concordium/concordium.github.io/blob/main/source/mainnet/docs/desktop-wallet/sign-transaction.rst](https://github.com/Concordium/concordium.github.io/blob/main/source/mainnet/docs/desktop-wallet/sign-transaction.rst)
4. [View transaction proposals](https://docs.concordium.com/en/mainnet/docs/desktop-wallet/proposed-transactions.html): [https://github.com/Concordium/concordium.github.io/blob/main/source/mainnet/docs/desktop-wallet/proposed-transactions.rst](https://github.com/Concordium/concordium.github.io/blob/main/source/mainnet/docs/desktop-wallet/proposed-transactions.rst)

Note: A separate review of language and style will be conducted after the technical review is complete.