Add basic versioning to ESPHome Builder

[Redsandro]

Describe the enhancement

I'd like to have "save points", snapshots, different versions of a config to be able to roll back to.

Use cases

When I expand on a yaml configuration and end up breaking it, too often do I struggle to get it back to when it was still working fine. One time it took weeks before I noticed a sensor wasn't working anymore. It would save time if I could just peek at last month's configuration to see what I did wrong.

Visual examples

Anything else?

Something simple. Any type of simple versioning would be helpful, as long as it's not too complex. If you want to hear one possible implementation, here's what I had in mind:

The yaml configuration now accepts a version: key. When using the wizard, it is automatically populated with CalVer.
Everything else works the same, although secretly the version is used to store a unique copy of the configuration. The user doesn't see this.

Now when the user changes the version value and saves, both versions becomes selectable from a dropdown.

When editing and saving an older version other than the newest, a dialog shows:

Saving will overwrite $old_version_number. It is recommended to save to a new configuration.

[Overwrite $old_version_number] [Save as new $fresh_new_calver] [Cancel]

The $fresh_new_calver option changes version: to the latest unused CalVer.

I wouldn't recommend an auto-increment function. It is not meant as a full versioning system replacement. Just a simple easy to understand feature that will save many people's day sometime. Users will learn once they alter the version and see the dropdown how this works.

With this system I would tinker until something is "stable" and then change the version next time I tinker, so I know I have a save and working version of the configuration stored.

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Extra

It might even be even extra super helpful if the latest firmwares (full and ota) are also stored together with the old configuration(s). Because if you have issues, and remember version 2023.4.1 (some old version) of your config was working, you would be recompiling with a fresh version 2026.1.1 of ESPHome. Sometimes there have been breaking changes. The dialog above would mention this:

Saving will overwrite $old_version_number and remove related firmware files. It is recommended to save to a new configuration.