This adds support for encoding YAML tags by specifying them in @yaml(tag="...") attributes on CUE fields. The tag value is applied to the encoded YAML node. This enables generating YAML files that use custom tags, like those required by authentik blueprints (!KeyOf, !Env, !Find, etc.) and other YAML-based tools that rely on tags for special processing. Tags can be applied to scalars, sequences, and mappings. The implementation extracts tags from field attributes in the AST and sets them on the corresponding yaml.Node during encoding. Fixes #2316 Closes #4199 as merged as of commit 1206905c8. Signed-off-by: Jonas Meyer-Ohle <19151471+jonas-meyer@users.noreply.github.com> Change-Id: Ibac6b3c97539a87e215821ffbb71735b4f5330d4 Reviewed-on: https://cue.gerrithub.io/c/cue-lang/cue/+/1231452 Reviewed-by: Daniel Martí <mvdan@mvdan.cc> Reviewed-by: Chief Cueckoo <chief.cueckoo@gmail.com> TryBot-Result: CUEcueckoo <cueckoo@cuelang.org> Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>