Offer supply suggestions, drop the circuit column, center cells

The Versorgung field suggests ELT and MSR (plus values already used in
the balance) through a datalist and still accepts free text. The circuit
number column is not needed in early design phases; it is removed from
the data model, the regenerated migration 0010, the editor and the
print. All cells are centered except "Verbraucher / Flächen", group
titles and total labels.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/frontend/estimate-balance/estimate-balance-document.ts

@@ -18,7 +18,6 @@ export const estimateTextLimits = {
   groupTitle: 200,
   groupEditor: 100,
   supply: 50,
-  circuitRef: 50,
   rowName: 200,
   remark: 500,
 } as const;
@@ -34,7 +33,6 @@ export function createEstimateRow(
     id: createId(),
     sortOrder,
     supply: null,
-    circuitRef: null,
     name: "",
     quantity: 1,
     unit: "piece",
@@ -257,7 +255,6 @@ export function toSaveableEstimateBalance(
         id: row.id,
         sortOrder: row.sortOrder,
         supply: optionalText(row.supply),
-        circuitRef: optionalText(row.circuitRef),
         name: requiredText(row.name),
         quantity: row.quantity,
         unit: row.unit,