Parameterize sensitive inputs before publishing .ad recordings #1348

Problem

Ordinary .ad recording must persist executable action inputs. Today that means a recorded fill value is serialized verbatim into the published script, including passwords or tokens. Diagnostic/event-log redaction does not make the executable artifact safe.

Native .ad replay already supports late-bound ${VAR} values supplied through --env/-e and AD_VAR_*. The missing capability is safe authoring: execute an interaction with the real value while publishing a placeholder, without ever writing the secret to the target or its temporary publication file.

This is deliberately separate from the active-session publication decision in #1346 / ADR 0016.

Desired outcome

Define and implement an explicit parameterization mechanism for sensitive recorded inputs. For example, an author could associate a recorded fill with PASSWORD, producing ${PASSWORD} in the .ad artifact while the live action receives the real value.

The design must not infer sensitivity solely from selector/field names, and it must preserve ADR 0012 provenance and atomic publication semantics.

Acceptance criteria

• A caller can explicitly mark a recorded input for publication as ${VAR} while supplying the real value only to the live interaction.
• The real value never reaches the .ad target, publication temp file, session event display, or diagnostics.
• Repeated and distinct sensitive values have deterministic placeholder mappings.
• Missing replay values fail before the corresponding interaction with an actionable error.
• Ordinary non-sensitive recordings keep their current literal-input behavior.
• CLI help explains the safe login/bootstrap workflow and warns that unparameterized fill values are literal script content.