ui/phase-15: planet inspector production controls + order-draft collapse

Adds the second end-to-end command (`setProductionType`) with a
collapse-by-`planetNumber` rule on the order draft, the segmented
production-controls component on the planet inspector, the FBS
encoder/decoder pair for `CommandPlanetProduce`, and the
`localShipClass` projection on `GameReport`. Forecast number is
deferred and tracked in the new `ui/docs/calc-bridge.md`.

ui/frontend/src/sync/order-draft.svelte.ts

@@ -173,11 +173,41 @@ export class OrderDraftStore {
 	 * triggers an auto-sync to keep the server in lock-step.
 	 * Mutations made before `init` resolves are ignored — the layout
 	 * always awaits `init` before exposing the store.
+	 *
+	 * `setProductionType` carries a collapse-by-`planetNumber` rule:
+	 * a new entry supersedes any prior `setProductionType` for the
+	 * same planet, so the draft holds at most one production choice
+	 * per planet at any time. Other variants append unconditionally —
+	 * `planetRename` keeps its append-only behaviour because each
+	 * rename is a distinct user-visible action.
 	 */
 	async add(command: OrderCommand): Promise<void> {
 		if (this.status !== "ready") return;
-		this.commands = [...this.commands, command];
-		this.statuses = { ...this.statuses, [command.id]: validateCommand(command) };
+		const removed: string[] = [];
+		let nextCommands: OrderCommand[];
+		if (command.kind === "setProductionType") {
+			nextCommands = [];
+			for (const existing of this.commands) {
+				if (
+					existing.kind === "setProductionType" &&
+					existing.planetNumber === command.planetNumber
+				) {
+					removed.push(existing.id);
+					continue;
+				}
+				nextCommands.push(existing);
+			}
+			nextCommands.push(command);
+		} else {
+			nextCommands = [...this.commands, command];
+		}
+		this.commands = nextCommands;
+		const nextStatuses = { ...this.statuses };
+		for (const id of removed) {
+			delete nextStatuses[id];
+		}
+		nextStatuses[command.id] = validateCommand(command);
+		this.statuses = nextStatuses;
 		await this.persist();
 		this.scheduleSync();
 	}
@@ -400,6 +430,20 @@ function validateCommand(cmd: OrderCommand): CommandStatus {
 	switch (cmd.kind) {
 		case "planetRename":
 			return validateEntityName(cmd.name).ok ? "valid" : "invalid";
+		case "setProductionType":
+			// Mirrors the engine's `subject=Production` validator
+			// (`game/internal/router/validator.go`): SCIENCE and SHIP
+			// require a non-empty entity-name-valid subject; the other
+			// six production types accept any subject (typically empty)
+			// because the engine only consults the subject for those
+			// two cases.
+			if (
+				cmd.productionType === "SCIENCE" ||
+				cmd.productionType === "SHIP"
+			) {
+				return validateEntityName(cmd.subject).ok ? "valid" : "invalid";
+			}
+			return "valid";
 		case "placeholder":
 			// Phase 12 placeholder entries are content-free and never
 			// transition out of `draft` — they are not submittable.