Add SPC convective outlook briefing module

docs/internal/module.md

@@ -37,6 +37,7 @@ The registry recognizes these IDs:
 - `derived_daypart_summaries`
 - `precip_timing`
 - `alert_digest`
+- `spc_convective_outlooks`
 - `area_forecast_discussion`
 - `weather_story`
 - `outdoor_windows`
@@ -45,9 +46,9 @@ The registry recognizes these IDs:
 Every registered module has a builder. Report composition entries that refer to
 unknown or unimplemented module IDs fail validation instead of being skipped.
 
-The package also defines `spc_convective_outlooks` and
-`spc_convective_discussion` IDs and empty option structs for the collected
-contract. They are not registered modules in the briefing registry.
+The package also defines the `spc_convective_discussion` ID and empty option
+struct for the collected contract. It is not a registered module in the
+briefing registry until its builder exists.
 
 ## Options