The conversion isn't implemented, but mostly isn't part of the language
specification. The behavior remains mostly unchanged, the resulting
error changes tho, still an error:

 - pre: type conversion error from 'int' to 'google.protobuf.Duration'
 - post: found no matching overload for 'duration' applied to '(int)'

Signed-off-by: Alex Snaps <asnaps@redhat.com>

* Update REPL to use proposed type spec language

Updates the REPL to use a proposed mini language for specifying types in
environment configs.

internal ref: http://cl/894210091

* Support shorthand types in env yaml and REPL

Adds support for shorthand types when describing environments.

Also rework repl to track types in terms of the environment config
TypeDesc. This removes many of the usages of deprecated APIs in the
REPL.

When ContextEval detects an InterruptError, wrap both the original
error and the context cause using fmt.Errorf("%w: %w", ...) so that:
- errors.Is(err, context.Canceled) works (new behavior)
- errors.Is(err, context.DeadlineExceeded) works (new behavior)
- errors.Is(err, InterruptError{}) works (preserved)
- strings.Contains(err.Error(), "operation interrupted") works (backward compat)

Previously, the error was replaced entirely with context.Cause(ctx),
which dropped the "operation interrupted" message that downstream
consumers (e.g. Kubernetes) rely on for string matching.

Fixes #1195 while maintaining backward compatibility.

Signed-off-by: Davanum Srinivas <davanum@gmail.com>

Use shorthand type specifiers in env yaml

Also add a test that JSON as yaml works.