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/shared/estimate-balance/estimate-balance.ts

@@ -12,10 +12,8 @@ export type EstimateRowConnection = "fixed" | "socket";
 export interface EstimateRowSnapshot {
   id: string;
   sortOrder: number;
-  /** Versorgung, e.g. "ELT" or "ISP". */
+  /** Versorgung, e.g. "ELT" or "MSR" (free text). */
   supply: string | null;
-  /** Optional circuit reference, free text. */
-  circuitRef: string | null;
   /** Verbraucher / Fläche. May be empty while a row is being typed. */
   name: string;
   /** Anzahl (unit "piece") or area in m² (unit "area"). */