Add configurable report module composition

docs/config.md

@@ -174,6 +174,41 @@ midday, afternoon, and evening.
 Recent Changes are added to prompt input when a prior comparable briefing
 snapshot exists and a threshold is crossed.
 
+### `reports`
+
+`reports` optionally overrides the ordered deterministic modules declared by
+built-in report definitions. Omit a report entry to use its built-in module
+order.
+
+Supported report keys are `daily`, `tomorrow`, `three_day`, `weekend`, and
+`storm`. Canonical report IDs such as `daily_today` and `daily_tomorrow` are
+also accepted.
+
+Each report entry supports:
+
+- `deterministic_modules`: ordered module list. Entries may be string module
+  IDs or objects with `id` and optional `options`.
+
+Example:
+
+```yaml
+reports:
+  daily:
+    deterministic_modules:
+      - metadata
+      - current_conditions
+      - id: area_forecast_discussion
+        options:
+          sections:
+            - short_term
+```
+
+Unknown reports, unknown modules, duplicate modules, incompatible report/module
+combinations, duplicate stanza names, and invalid options fail config loading.
+`area_forecast_discussion.options.sections` may contain `product`,
+`key_messages`, `short_term`, and `long_term`. Empty or omitted `sections`
+includes all available AFD sections.
+
 ## Secrets
 
 Configuration files should not contain raw secrets. Use `secrets.directory` to