[16.0][ADD] repair_custom_sender: Allows configuring a custom sender email for repair orders

[nicolas-delbovier-acsone]

Use case

By default, Odoo sets the sender as the user who clicks "Send" on the wizard. This module allows setting a centralized generic email (e.g., repairs@company.com) for all repair communications.

Configuration

Technical note

I first tried to implement this by passing "default_email_from" in context but it seems this approach does not work as the email_from field gets overwritten later down the line. If you have an idea of how to make this work / why this does not work, I'd be happy ton hear it (I believe this would be a more elegant solution to ensure the wizard gets created with the good values at creation instead of having to overwrite)

[nicolas-delbovier-acsone]

Closing Rationale

Closing this PR to rework the implementation.

Key findings:

• The From header is easily managed via standard Mail Templates.
• However, Odoo's _notify_get_reply_to logic forces the Reply-To back to the catchall (in case of a mail.thread object), even when templates specify otherwise.

The objective is to ensure Reply-To remains synced with the custom From address. I will submit a new PR that specifically targets this.

[nicolas-delbovier-acsone]

See #162