Simplify and rationalize the hourly report template

docs/internal/generatedtext.md

@@ -29,14 +29,15 @@ The hourly generated text JSON accepts:
 ```json
 {
   "summary": "string",
-  "timing": "string",
-  "impacts": "string",
+  "forecast_discussion": "string",
+  "precipitation_timing": "string",
   "confidence": "string"
 }
 ```
 
-`summary`, `timing`, and `impacts` are required after trimming whitespace.
-`confidence` is optional and omitted from normalized JSON when blank.
+`summary` and `forecast_discussion` are required after trimming whitespace.
+`precipitation_timing` and `confidence` are optional and omitted from normalized
+JSON when blank.
 
 ## Boundaries
 
@@ -54,7 +55,7 @@ The hourly generated text JSON accepts:
 - Malformed generated-text JSON fails with decode context.
 - Unknown generated-text JSON fields fail during decoding.
 - Empty required hourly fields fail after trimming whitespace.
-- Missing required render-context stanzas fail with the stanza name.
+- Missing optional render-context stanzas become nil module pointers.
 - Invalid render metadata, including missing timezone, missing generated time,
   or invalid valid period, fails before template rendering.
 

docs/internal/reporttemplate.md

@@ -61,12 +61,11 @@ The hourly GeneratedText schema describes the structured prose Scriptorium is
 expected to write for the prompt. It requires:
 
 - `summary`
-- `timing`
-- `impacts`
+- `forecast_discussion`
 
-It allows optional `confidence` and rejects additional properties. Weather truth
-remains in module outputs; GeneratedText is limited to prose slots consumed by
-the template.
+It allows optional `precipitation_timing` and `confidence`, and rejects
+additional properties. Weather truth remains in module outputs; GeneratedText is
+limited to prose slots consumed by the template.
 
 ## Failure Behavior