fix(bienvenida): wire the welcome screen into the first-launch flow

openspec/changes/rediseno-funcional/tasks.md

@@ -16,6 +16,11 @@
 > **WU15b was added mid-apply, not planned upfront** — WU15 shipped `PantallaGrabaciones` (the recordings library)
 > fully tested but reachable from nowhere in the app. WU15b (below, after WU15's section) is the coordinator-ruled fix
 > that wires it into Settings navigation. It is small and does not change the 18-commit delivery model's shape.
+> **WU17b was added mid-apply, not planned upfront — same shape as WU15b.** WU17 shipped `PantallaBienvenida` (the
+> welcome screen) fully tested but reachable from nowhere in the app (`rg "PantallaBienvenida" lib/app.dart lib/main.dart`
+> found nothing). WU17b (below, after WU17's section) wires it into the genuine first-launch flow and establishes how
+> it coexists with the pre-existing, unrelated `PluriOnboardingDialog` ("what's new" modal). It is small and does not
+> change the 18-commit delivery model's shape.
 > Strict TDD is ON. Runner: `flutter test`. `flutter analyze` and a **scoped** `dart format` gate every commit.
 > **`flutter build` is never run.**
 >
@@ -1058,6 +1063,61 @@ real capability living in the header, not decorative chrome).
        `lib/l10n/app_*.arb` or `lib/`.
 - [x] 17.7 Verify — all 3 scenario tests green; grep scan clean.
 
+## WU17b — Wire the welcome screen into the first-launch flow
+
+**Not in the original plan — added to close the WU17 gap noted above, same shape as WU15/WU15b.** WU17 built
+`PantallaBienvenida` fully tested and committed, but left it unreachable from the app: `rg "PantallaBienvenida"
+lib/app.dart lib/main.dart` found nothing. This work unit exists solely to fix that.
+
+**Commit**: `fix(bienvenida): wire the welcome screen into the first-launch flow`
+**Depends on**: WU17
+**Spec refs**: `onboarding-welcome` — Full-Screen Welcome Route (reachability; the render/content/no-monetization/CTA
+scenarios stay WU17's own, unmodified)
+**Verify**: `flutter test test/servicios/servicio_bienvenida_test.dart test/pantallas/pantalla_bienvenida_primer_lanzamiento_test.dart test/pantallas/pantalla_bienvenida_test.dart test/widget_test.dart && flutter analyze && dart format --set-exit-if-changed $(git diff --cached --name-only --diff-filter=ACM HEAD -- '*.dart')`
+**New tests**: `test/servicios/servicio_bienvenida_test.dart`, `test/pantallas/pantalla_bienvenida_primer_lanzamiento_test.dart`
+**Modified tests**: none (WU17's own `pantalla_bienvenida_test.dart` re-run unmodified as a regression check)
+
+**Coexistence ruling applied.** `PluriOnboardingDialog` (an unrelated, pre-existing "what's new"/help-content modal
+loaded from markdown assets) is NOT deleted, merged, or replaced — first-launch welcome and a what's-new modal are
+different things, confirmed by reading `assets/content/onboarding/en.md`: it is a detailed feature-reference
+walkthrough plus per-version update notes, structurally different content from the welcome screen's 3-bullet
+marketing intro. Both now run from `app.dart`'s `_PaginaPrincipalState`, in this order on every cold start: the
+welcome screen's once-ever check resolves FIRST, then the pre-existing what's-new dialog's own independent
+per-version due-or-not check runs exactly as it did before this WU. Sequencing (not two independent fire-and-forget
+calls) is what prevents the two from ever racing onto the screen at the same time.
+
+- [x] 17b.1 RED — `test/servicios/servicio_bienvenida_test.dart`: a new `ServicioBienvenida` (mirroring
+      `ServicioContenidoApp`'s injectable-`SharedPreferences`, versioned-key convention, S3-R4) is due before it has
+      ever been marked seen, is not due after `marcarBienvenidaVista()`, and respects a seen flag already persisted
+      by a prior launch (`SharedPreferences.setMockInitialValues`).
+- [x] 17b.2 RED — `test/pantallas/pantalla_bienvenida_primer_lanzamiento_test.dart`: a new
+      `PantallaBienvenida.mostrarSiProcede(context)` static method (mirroring `PluriOnboardingDialog.mostrarSiProcede`'s
+      check-then-show-then-mark-seen shape) pushes the welcome screen on a first launch (no seen flag persisted), does
+      NOT push it when the seen flag is already persisted, and — in one continuous session — persists the flag after
+      being shown once so a later check in the same run skips it.
+- [x] 17b.3 GREEN — created `lib/servicios/servicio_bienvenida.dart` (`ServicioBienvenida`, key
+      `pluri_bienvenida_vista_v1`, plain one-time boolean — no version comparison needed, unlike
+      `ServicioContenidoApp`, since this welcome is a single first-impression surface, not a per-version one).
+- [x] 17b.4 GREEN — added the static `PantallaBienvenida.mostrarSiProcede(BuildContext)` method to the existing
+      `pantalla_bienvenida.dart` file (no new wrapper class needed — unlike `PluriOnboardingDialog`, there is only one
+      call shape here); updated the class doc comment to describe how it coexists with `PluriOnboardingDialog`.
+- [x] 17b.5 GREEN — wired `app.dart`: imported `pantalla_bienvenida.dart`; renamed the existing
+      `_onboardingInicialSolicitado` guard flag to `_flujoPrimerLanzamientoSolicitado` (it now covers the combined
+      sequence, not only the dialog); added `_mostrarFlujoPrimerLanzamiento()`, which awaits
+      `PantallaBienvenida.mostrarSiProcede(context)` then calls the pre-existing, untouched
+      `_mostrarOnboardingInicial()` — replacing the single `unawaited(_mostrarOnboardingInicial())` call site with
+      `unawaited(_mostrarFlujoPrimerLanzamiento())`.
+- [x] 17b.6 REFACTOR — confirmed `_mostrarOnboardingInicial()`'s own body (900ms delay, `_alarmaSonandoActiva` guard,
+      `PluriOnboardingDialog.mostrarSiProcede` call) is byte-for-byte unchanged — only its call site moved one level
+      deeper into the new sequencing method. No scenario in `PantallaBienvenida`'s own WU17 test file needed to
+      change (all 3 pass unmodified, confirming the CTA/content/no-monetization behavior is untouched).
+- [x] 17b.7 Verify — scoped suite green: 13/13 (3 `servicio_bienvenida_test.dart` + 3
+      `pantalla_bienvenida_primer_lanzamiento_test.dart` + 3 `pantalla_bienvenida_test.dart` [byte-identical,
+      unmodified] + 4 `widget_test.dart`). `flutter analyze`: 1 issue, identical to baseline. Scoped `dart format`:
+      reformatted 1 of 5 touched files (whitespace-only string-literal wrapping), stable on re-run. Literal-encoding
+      scan: one console-rendering false positive on the pre-existing "días" string (verified byte-correct UTF-8 via a
+      direct file read with the encoding pinned), zero real corruption.
+
 ## WU18 — i18n batch (all 13 locales)
 
 **Commit**: `feat(i18n): add redesign strings and translate Escuchar rename to 11 locales`