fix: recargar programa de obra (v_row no es una tabla)

<!-- CURSOR_AGENT_PR_BODY_BEGIN -->
## Problema

Tras el #21 el GET ya no choca por agregados anidados, pero al recargar aparece:

`fn_work_program_get (sqlstate=42P01): missing FROM-clause entry for table "v_row"`

`v_row` es `jsonb`. Escribir `v_row.value` lo toma Postgres como `tabla.columna`, no como campo del JSON.

El #21 destapó este bug: el 42803 cortaba antes de llegar al loop.

## Cambio

Changeset **037** (no se edita el 036, ya corrido). La curva se arma en SQL (subquery + `SUM() OVER`) sin el `FOR` ni `v_row.value`.

## Cómo probar

1. Mergear este PR y aplicar Liquibase (037).
2. Abrir Programa de obra en la obra que ya importaste. Debe cargar sin toast rojo.
3. Recargar la página: igual.
4. Si hace falta, volver a Importar el Excel por partida y confirmar que se ve el programa.

<!-- CURSOR_AGENT_PR_BODY_END -->

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db/core/changelog-master.xml

@@ -46,5 +46,6 @@
   <include file="changesets/034-fn-expense-update-reclassify.sql" relativeToChangelogFile="true"/>
   <include file="changesets/035-warehouse-materials-catalog.sql" relativeToChangelogFile="true"/>
   <include file="changesets/036-fn-work-program-get-curve.sql" relativeToChangelogFile="true"/>
+  <include file="changesets/037-fn-work-program-get-curve-vrow.sql" relativeToChangelogFile="true"/>
 
 </databaseChangeLog>

db/core/changesets/037-fn-work-program-get-curve-vrow.sql

@@ -0,0 +1,85 @@
+--liquibase formatted sql
+-- PANELS · core · fn_work_program_get: v_row es jsonb, no un record (.value = 42P01)
+
+--changeset panel:core-037-fn-work-program-get-curve-vrow splitStatements:false
+CREATE OR REPLACE FUNCTION core.fn_work_program_get(payload jsonb)
+RETURNS jsonb
+LANGUAGE plpgsql
+SECURITY INVOKER
+SET search_path = core
+AS $$
+DECLARE
+  v_project_id bigint := NULLIF(payload->>'project_id', '')::bigint;
+  v_program jsonb;
+  v_periods jsonb;
+  v_budget_total numeric(14,2);
+  v_curve jsonb;
+BEGIN
+  IF v_project_id IS NULL THEN
+    RETURN core.rpc_err('VALIDATION', 'fn_work_program_get: project_id es obligatorio',
+      jsonb_build_object('fn', 'fn_work_program_get'));
+  END IF;
+
+  SELECT to_jsonb(wp) INTO v_program
+  FROM work_programs wp WHERE wp.project_id = v_project_id;
+
+  IF v_program IS NULL THEN
+    SELECT COALESCE(SUM(amount), 0) INTO v_budget_total FROM budget_items WHERE project_id = v_project_id;
+    RETURN core.rpc_ok(
+      jsonb_build_object(
+        'program', NULL,
+        'periods', '[]'::jsonb,
+        'budget_subtotal', v_budget_total,
+        'curve', '[]'::jsonb
+      ),
+      format('Proyecto %s sin programa de obra', v_project_id),
+      jsonb_build_object('fn', 'fn_work_program_get', 'project_id', v_project_id)
+    );
+  END IF;
+
+  SELECT COALESCE(jsonb_agg(to_jsonb(p) ORDER BY p.period_index), '[]'::jsonb) INTO v_periods
+  FROM work_program_periods p WHERE p.program_id = (v_program->>'id')::bigint;
+
+  SELECT COALESCE(SUM(amount), 0) INTO v_budget_total FROM budget_items WHERE project_id = v_project_id;
+
+  -- Sin FOR + v_row.value (eso lo toma Postgres como tabla.columna → 42P01).
+  -- SUM de montos en subquery; jsonb_agg y el acumulado van en capas distintas
+  -- para no anidar agregados (42803).
+  SELECT COALESCE(jsonb_agg(to_jsonb(y) ORDER BY y.period_index), '[]'::jsonb)
+  INTO v_curve
+  FROM (
+    SELECT
+      x.period_index,
+      x.label,
+      x.amount,
+      CASE WHEN v_budget_total > 0 THEN round(x.amount / v_budget_total, 6) ELSE 0 END AS pct_period,
+      CASE WHEN v_budget_total > 0
+        THEN round(SUM(x.amount) OVER (ORDER BY x.period_index) / v_budget_total, 6)
+        ELSE 0
+      END AS pct_cumulative
+    FROM (
+      SELECT
+        pr.period_index,
+        pr.label,
+        round(COALESCE(SUM(pa.amount), 0), 2) AS amount
+      FROM work_program_periods pr
+      LEFT JOIN work_program_partida_amounts pa ON pa.period_id = pr.id
+      WHERE pr.program_id = (v_program->>'id')::bigint
+      GROUP BY pr.period_index, pr.label
+    ) x
+  ) y;
+
+  RETURN core.rpc_ok(
+    jsonb_build_object(
+      'program', v_program,
+      'periods', v_periods,
+      'budget_subtotal', v_budget_total,
+      'curve', v_curve
+    ),
+    format('Programa de obra del proyecto %s', v_project_id),
+    jsonb_build_object('fn', 'fn_work_program_get', 'project_id', v_project_id)
+  );
+EXCEPTION WHEN OTHERS THEN
+  RETURN core.rpc_from_exception('fn_work_program_get', SQLSTATE, SQLERRM);
+END;
+$$;