Move the Alert Digest into a shared partial template, and add it to the today, tomorrow, and daily reports

docs/templates.md

@@ -16,6 +16,7 @@ are:
 
 Shared named partials live under `internal/reporttemplate/templates/partials/`:
 
+- `alert_digest.md.tmpl`, used by Daily, Today, Tomorrow, and Hourly
 - `daypart_forecast.md.tmpl`, used by Daily and Tomorrow
 - `today_daypart_forecast.md.tmpl`, used by Today
 - `precipitation_timing.md.tmpl`, used by Daily, Today, Tomorrow, and Hourly
@@ -113,8 +114,8 @@ Tomorrow generated text uses the same `.GeneratedText.Summary`,
 Hourly. `.GeneratedText.ForecastDiscussion` is a slice of paragraphs and should
 be rendered with `range`.
 
-Tomorrow uses the shared `daypart_forecast` and `precipitation_timing`
-partials.
+Tomorrow uses the shared `alert_digest`, `daypart_forecast`, and
+`precipitation_timing` partials.
 
 Tomorrow modules include the Hourly module fields plus:
 
@@ -144,7 +145,8 @@ Daily generated text uses `.GeneratedText.Summary`,
 `.GeneratedText.Confidence`. Forecast discussion is a slice of paragraphs and
 should be rendered with `range`.
 
-Daily uses the shared `daypart_forecast` and `precipitation_timing` partials.
+Daily uses the shared `alert_digest`, `daypart_forecast`, and
+`precipitation_timing` partials.
 
 Daily uses template ID `daily`, generated-text schema ID `daily`, and prompt
 source `internal/reporttemplate/prompts/daily.generated_text.md`.
@@ -179,7 +181,7 @@ should be rendered with `range`.
 
 Today uses the `today_daypart_forecast` partial so elapsed or missing dayparts
 can be omitted while Daily and Tomorrow keep their fallback row. It also uses
-the shared `precipitation_timing` partial.
+the shared `alert_digest` and `precipitation_timing` partials.
 
 Today uses template ID `today`, generated-text schema ID `today`, and prompt
 source `internal/reporttemplate/prompts/today.generated_text.md`.