feat: Implement default API site seeding, add a dialect-aware setting upsert utility, and introduce check-in API routes with background task processing.

src/server/services/backupService.ts

@@ -1,6 +1,7 @@
 import { asc } from 'drizzle-orm';
 import cron from 'node-cron';
 import { db, schema } from '../db/index.js';
+import { upsertSetting } from '../db/upsertSetting.js';
 
 const BACKUP_VERSION = '2.0';
 
@@ -558,13 +559,7 @@ async function importPreferencesSection(section: PreferencesBackupSection): Prom
     for (const row of section.settings) {
       if (!isSettingValueAcceptable(row.key, row.value)) continue;
 
-      await tx.insert(schema.settings).values({
-        key: row.key,
-        value: stringifySettingValue(row.value),
-      }).onConflictDoUpdate({
-        target: schema.settings.key,
-        set: { value: stringifySettingValue(row.value) },
-      }).run();
+      await upsertSetting(row.key, row.value, tx);
       applied.push({ key: row.key, value: row.value });
     }
   });

src/server/services/defaultSiteSeedService.ts

@@ -1,5 +1,6 @@
 import { eq } from 'drizzle-orm';
 import { db, schema } from '../db/index.js';
+import { upsertSetting } from '../db/upsertSetting.js';
 
 export const DEFAULT_SITE_SEED_SETTING_KEY = 'default_site_seed_v1';
 
@@ -53,16 +54,7 @@ type SeedSummary = {
 };
 
 async function writeSeedMarker(tx: typeof db) {
-  await tx.insert(schema.settings)
-    .values({
-      key: DEFAULT_SITE_SEED_SETTING_KEY,
-      value: JSON.stringify(true),
-    })
-    .onConflictDoUpdate({
-      target: schema.settings.key,
-      set: { value: JSON.stringify(true) },
-    })
-    .run();
+  await upsertSetting(DEFAULT_SITE_SEED_SETTING_KEY, true, tx);
 }
 
 export async function ensureDefaultSitesSeeded(): Promise<SeedSummary> {