Complete input destination implementation audit

docs/internal/overview.md

@@ -8,8 +8,10 @@ private state; public signatures and fields do not expose engine types.
 Implemented component owners:
 
 - `internal/engine` owns host and native-filesystem source acquisition,
-  grouped strict composition, recursive precedence assembly, and destination-local
-  sibling inheritance before typed decoding. It also owns schema
+  grouped strict composition, recursive precedence assembly, per-input mapping
+  placement within that assembly, and destination-local sibling inheritance
+  before typed decoding. It retains source placement alongside physical source
+  identity and owns schema
   inspection, lifecycle coordination, callback auditing,
   provenance/history, passive source-context retention, secret resolution and
   bootstrap, safe inspection rendering, and effective-value comparison over
@@ -41,11 +43,13 @@ these constraints and rejects exported aliases, fields, or signatures involving
 internal types.
 
 The [configuration contract](../config.md) owns implemented YAML and lifecycle
-semantics, including [effective configuration diffs](../config.md#effective-configuration-diffs).
+semantics, including [input destinations](../config.md#input-destinations) and
+[effective configuration diffs](../config.md#effective-configuration-diffs).
 The [consumer adoption guide](../consumers/README.md) owns application guidance.
 The [architecture policy](../policy/architecture.md) owns contributor
 boundaries; [ADR 0006](../adr/0006-public-facade.md) records the facade decision
 and [ADR 0010](../adr/0010-effective-configuration-diff.md) records the diff
+decision; [ADR 0011](../adr/0011-input-destinations.md) records the placement
 decision. See the [development guide](../development.md) for validation commands
 and [release procedure](../release.md) for source-candidate gates. [ADR
 0009](../adr/0009-sibling-inheritance.md) records why inheritance is a built-in