awf v0.4.0

A workflow-format release adding input-parameterizable agent roles: a reusable
role's model/system_prompt/top-level-string with: may reference
{{ input.* }}, resolved against the owning module's run input at step
execution, so one --input steers a whole fleet and forwards across a call:
boundary into a child workflow's own role. The workflow-format version
(version: 1) is unchanged.

Added

• Input-parameterizable agent roles. A role's model/system_prompt/top-level
  string with: values may reference {{ input.* }}, resolved against the owning
  module's run input at step execution — so one awf run --input model=… steers a
  whole fleet, and a child workflow's own role reads a model forwarded via
  call: input:. Guarded by AWF1067 (input.* only; no nested templates).
  Behavior change: a role with: value that previously carried a literal
  non-input {{ … }} (e.g. {{ run.id }}) — which used to pass validation
  and reach the adapter as literal text — now fails validation with AWF1067.