Remove obsolete briefing snapshot artifacts

docs/internal/briefing.md

@@ -4,9 +4,9 @@ This document describes the implemented briefing package boundary.
 
 ## Purpose
 
-`internal/briefing` builds structured report-specific briefing packages from
-resolved report metadata, collected weather data, and derived forecast facts.
-Briefings are curated inputs for prompt data packages, not rendered report prose.
+`internal/briefing` builds prompt-facing module values from resolved report
+metadata, collected weather data, and derived forecast facts. These values are
+curated prompt inputs, not rendered report prose or durable report snapshots.
 
 ## Inputs And Outputs
 
@@ -19,23 +19,19 @@ Inputs:
 
 Outputs:
 
-- `briefing.Package` with common metadata and one report-specific content
-  object for Daily, 3-Day, Weekend, or Storm Report
 - module registry definitions for known module IDs, stanza names, option
   shapes, fact requirements, report compatibility, and missing-data behavior
 - source-oriented module outputs for `metadata`, `current_conditions`,
   `alert_digest`, `area_forecast_discussion`, and `weather_story`
-- optional `currentConditions` prompt context from normalized
-  `/conditions/current` data when available
-- optional structured `weatherStory` context on report-specific briefing
-  objects when `/weatherstories/latest` is available
-- optional JSON file written by `briefing.Save`
+- derived module outputs such as daily summaries, daypart summaries,
+  precipitation timing, outdoor windows, and tomorrow planning
+- optional current conditions and weather story module outputs when those
+  Weather API sources are available
 
 ## Boundaries
 
 - This package selects and shapes weather facts for prompts.
-- It owns module registry validation, but app orchestration does not execute
-  modules yet.
+- It owns module registry validation and module builder behavior.
 - It does not fetch weather data, compare prior snapshots, build
   `data_package` files, invoke Scriptorium, or write workflow metadata.
 
@@ -54,23 +50,18 @@ None directly.
 
 ## State Or Manifest Behavior
 
-`briefing.Save` writes briefing JSON atomically. Managed workspace placement is
-owned by `internal/state`.
+None. Module snapshots and prompt input data packages are persisted by
+`internal/state` and composed by `internal/app`.
 
 ## Skip And Resume Behavior
 
-None. Builders either return a complete briefing package or an error.
+None. Builders either return a module output, omit optional unavailable data,
+or return an error for invalid required inputs.
 
 ## Failure Behavior
 
-- Daily briefing construction requires a Daily report definition and derived
-  daily summary.
-- 3-Day briefing construction requires a 3-Day report definition and at least
-  one derived summary.
-- Weekend briefing construction requires a Weekend report definition and at
-  least one derived summary.
-- Storm briefing construction requires a Storm Report definition and forecast
-  bundle.
+- Required derived modules return errors when their dependent facts are not
+  available.
 - Module registry construction rejects duplicate module IDs and duplicate
   stanza names.
 - Module composition validation rejects unknown modules, duplicate modules,
@@ -79,23 +70,19 @@ None. Builders either return a complete briefing package or an error.
   forecast discussion, and weather story stanzas.
 - Alert digest output distinguishes checked empty alert data from missing alert
   source data.
-- Save failures include path and operation context.
 
 ## Tests
 
 Inspect:
 
-- `internal/briefing/daily_test.go`
-- `internal/briefing/three_day_test.go`
-- `internal/briefing/weekend_test.go`
-- `internal/briefing/storm_test.go`
 - `internal/briefing/base_modules_test.go`
+- `internal/briefing/derived_modules_test.go`
 - `internal/briefing/modules_test.go`
 - `internal/app/app_test.go`
 
 ## Invariants
 
-- Briefings contain structured weather facts and source context.
+- Module outputs contain structured weather facts and source context.
 - Common metadata includes RunID, report ID, prompt ID, valid period, source
   provenance, source hashes, source warnings, and configured prompt location.
 - LLM prompt input packaging and Scriptorium execution remain outside this