Extract explicit configuration loading phases

docs/internal/overview.md

@@ -31,7 +31,9 @@ module and package documentation boundary. Its implemented public primitives are
 - strict schema-driven decoding over detached defaults in `decode.go`, including
   mapping/sequence semantics, null and numeric policy, safe codec errors, presence,
   baseline/final trees, and initial default/input origins;
-- public lifecycle coordination in `load.go`, bounded canonical import DFS in
+- public lifecycle coordination in `load.go`, option selection in `options.go`,
+  input assembly in `load_input.go`, typed phases/publication in `load_result.go`,
+  bounded canonical import DFS in
   `imports.go`, filesystem context/containment in `filesystem.go`, directive
   parsing/restrictions in `directives.go`, pattern-directed glob expansion in
   `glob.go`, version-report contexts