Reconcile lifecycle documentation

docs/internal/artifacts.md

@@ -45,6 +45,15 @@ ID.
 - `available`: local file exists and validates;
 - `provenance`: availability source.
 
+Configured definitions are always registered. Without an explicit selection,
+the effective analyze set contains enabled definitions. With `--artifacts`, the
+exact named configured definitions become the effective set for that invocation,
+regardless of their `enabled` value; dependencies are not added implicitly.
+Availability is separate from executability: a non-executable configured output
+may be reused from a canonical non-empty file, while an executable definition
+is generated by analyze. Extraction entries are registered from configuration
+and become available only after compatible extraction evidence is hydrated.
+
 Current provenance values:
 
 - `generated.current_analyze_run`
@@ -81,6 +90,10 @@ Previous-session sources (`narratio.previous_session.artifact.*`):
 - prefer manifest-backed previous-input paths;
 - fallback to existing previous-cache filesystem paths.
 
+Source absence is evaluated by the consuming artifact input. An optional input
+is omitted from that invocation; a required input fails resolution. This is
+separate from a stage's lifecycle outcome.
+
 Validation by content type:
 
 - transcript JSON built-ins: JSON with top-level `segments` array;