## Problem
In workflow YAML files, writing `if: foo == bar` shows an error because `foo` and `bar` are not valid contexts. However, the same invalid expression in an action.yml file showed no error.
## Solution
Add expression validation for implicit `if` conditions in action.yml files, matching the behavior of workflow YAML validation.
## What's new
1. **Pre-if/post-if validation** (node and docker actions)
- `pre-if: foo == bar` now shows error for unknown context
- `post-if: unknownFunc()` now shows error for unknown function
2. **Composite step `if` validation** (fix)
- Errors from `convertToIfCondition` were being lost due to call ordering
- Now captured correctly by calling conversion before retrieving errors
## Why the refactor?
The diff includes consolidating multiple validation loops into a single `validateAllTokens()` traversal. This matches the pattern used in workflow YAML validation (`additionalValidations`), making the code consistent between the two validation paths.
eric sciple
d2f52a9043