feat(11-01): schema, service, and tests for sort_order + reorderCandidates

- Add sortOrder REAL column to threadCandidates schema (default 0)
- Add sort_order column to test helper CREATE TABLE
- Add reorderCandidatesSchema to shared/schemas.ts
- Add ReorderCandidates type to shared/types.ts
- getThreadWithCandidates now orders candidates by sort_order ASC
- createCandidate appends at max sort_order + 1000 (first = 1000)
- Add reorderCandidates service function (transaction, active-only guard)
- Add 5 new tests: ordering, appending, reorder success, resolved guard, missing thread

src/server/services/thread.service.ts

@@ -1,4 +1,4 @@
-import { desc, eq, sql } from "drizzle-orm";
+import { asc, desc, eq, max, sql } from "drizzle-orm";
 import { db as prodDb } from "../../db/index.ts";
 import {
 	categories,
@@ -6,7 +6,11 @@ import {
 	threadCandidates,
 	threads,
 } from "../../db/schema.ts";
-import type { CreateCandidate, CreateThread } from "../../shared/types.ts";
+import type {
+	CreateCandidate,
+	CreateThread,
+	ReorderCandidates,
+} from "../../shared/types.ts";
 
 type Db = typeof prodDb;
 
@@ -83,6 +87,7 @@ export function getThreadWithCandidates(db: Db = prodDb, threadId: number) {
 		.from(threadCandidates)
 		.innerJoin(categories, eq(threadCandidates.categoryId, categories.id))
 		.where(eq(threadCandidates.threadId, threadId))
+		.orderBy(asc(threadCandidates.sortOrder))
 		.all();
 
 	return { ...thread, candidates: candidateList };
@@ -141,6 +146,14 @@ export function createCandidate(
 		imageFilename?: string;
 	},
 ) {
+	const maxRow = db
+		.select({ maxOrder: max(threadCandidates.sortOrder) })
+		.from(threadCandidates)
+		.where(eq(threadCandidates.threadId, threadId))
+		.get();
+
+	const nextSortOrder = (maxRow?.maxOrder ?? 0) + 1000;
+
 	return db
 		.insert(threadCandidates)
 		.values({
@@ -155,6 +168,7 @@ export function createCandidate(
 			status: data.status ?? "researching",
 			pros: data.pros ?? null,
 			cons: data.cons ?? null,
+			sortOrder: nextSortOrder,
 		})
 		.returning()
 		.get();
@@ -203,6 +217,35 @@ export function deleteCandidate(db: Db = prodDb, candidateId: number) {
 	return candidate;
 }
 
+export function reorderCandidates(
+	db: Db = prodDb,
+	threadId: number,
+	orderedIds: ReorderCandidates["orderedIds"],
+): { success: boolean; error?: string } {
+	return db.transaction((tx) => {
+		const thread = tx
+			.select()
+			.from(threads)
+			.where(eq(threads.id, threadId))
+			.get();
+		if (!thread) {
+			return { success: false, error: "Thread not found" };
+		}
+		if (thread.status !== "active") {
+			return { success: false, error: "Thread not active" };
+		}
+
+		for (let i = 0; i < orderedIds.length; i++) {
+			tx.update(threadCandidates)
+				.set({ sortOrder: (i + 1) * 1000 })
+				.where(eq(threadCandidates.id, orderedIds[i]))
+				.run();
+		}
+
+		return { success: true };
+	});
+}
+
 export function resolveThread(
 	db: Db = prodDb,
 	threadId: number,