Keep generated prose out of Markdown structure

docs/templates.md

@@ -47,6 +47,11 @@ from rendering.
   calculations, source selection, or prompt-input shaping to a template.
 - Keep generated prose in `.GeneratedText`; do not restate deterministic facts
   in generated prose merely to compensate for a template change.
+- Render every `.GeneratedText` value through `plainText`. It preserves prose
+  and paragraph breaks while escaping Markdown and HTML syntax, removing code
+  indentation, and replacing control characters. Never interpolate generated
+  prose directly: repository templates alone own headings, lists, links, and
+  other Markdown structure.
 - When changing the generated-prose contract, update the matching prompt,
   schema, validator, render context, and template together. The validation and
   catalog rules are owned by [Generated Text internals](internal/generatedtext.md).
@@ -69,7 +74,7 @@ Minimal list pattern:
 
 ```gotemplate
 {{ range .GeneratedText.ForecastDiscussion }}
-{{ . }}
+{{ plainText . }}
 {{ end }}
 ```
 
@@ -82,6 +87,7 @@ Templates have these helpers in addition to Go template built-ins:
 | `hasRelevantAlerts` | an alert-digest value or pointer | its `Relevant` slice is nonempty |
 | `hasEnhancedOrHigherSPCRisk` | an SPC outlook value or pointer | its `RiskDigest` contains an Enhanced, Moderate, or High Risk entry |
 | `isEnhancedOrHigherSPCRisk` | one SPC risk-digest entry | its `LabelText`, or fallback `RiskLabel`, is Enhanced, Moderate, or High Risk |
+| `plainText` | a generated prose string | a readable plain-text rendering that preserves paragraph breaks without allowing dynamic Markdown or HTML structure |
 
 For example, the alert partial uses the first two functions to decide whether
 to render the section: