Add a feature roadmap and staged implementation plan to refactor shared D&D module assets

docs/policy/development.md

@@ -51,6 +51,23 @@ go test ./internal/modules/extract/dnd/spells
 go test ./internal/modules/output/json
 ```
 
+## Prompt Asset Tests
+
+Tests should not assert the exact text of embedded prompt assets for production
+modules. Prompt wording is expected to change frequently during development, and
+tests should not fail solely because prompt prose was edited.
+
+Prefer assertions against prompt structure, prompt IDs and versions, declared
+inputs, schema wiring, input propagation, diagnostics redaction, and successful
+prompt preparation.
+
+Narrow exceptions:
+
+- generic or test-only modules may use fixed prompt text assertions when the
+  text is part of the test surface;
+- test fixtures may supply their own prompt text and assert against that fixture
+  text.
+
 ## Go Conventions
 
 - Prefer the standard library unless a dependency is justified by correctness,