templates: switch the default image from ubuntu-25.10 to ubuntu-26.04

[AkihiroSuda]

Fix #4792
Fix #5069

Note: used Claude

[unsuman]

Thanks

[jandubois]

I assume this is meant to be a temporary hack.

For a permanent feature it just feels wrong to abuse the param mechanism to avoid adding a field to the limayaml struct, but still reference it from builtin boot scripts.

[AkihiroSuda]

I assume this is meant to be a temporary hack.

Yes

For a permanent feature it just feels wrong to abuse the param mechanism to avoid adding a field to the limayaml struct, but still reference it from builtin boot scripts.

Shall we have a prefix like internal.lima-vm.io/ for internal params?

[afbjorklund]

I think you should just add it to the limayaml instead of using the params for this.

[AkihiroSuda]

I think you should just add it to the limayaml instead of using the params for this.

I don't want to add a proper YAML property for a temporary hack

[AkihiroSuda]

lima/pkg/limayaml/validate.go

Lines 397 to 409 in f6b7a0c

	// Validate Param settings
	// Names must start with a letter, followed by any number of letters, digits, or underscores
	validParamName := regexp.MustCompile(`^[a-zA-Z][a-zA-Z0-9_]*$`)
	for param, value := range y.Param {
	if !validParamName.MatchString(param) {
	errs = errors.Join(errs, fmt.Errorf("param %#q name does not match regex %#q", param, validParamName.String()))
	}
	for _, r := range value {
	if !unicode.IsPrint(r) && r != '\t' && r != ' ' {
	errs = errors.Join(errs, fmt.Errorf("param %#q value contains unprintable character %#q", param, r))
	}
	}
	}

Looks like we can't have a prefix like internal.lima-vm.io/.
We can still have one like internal_ ?

[jandubois]

Thanks, LGTM