fix: title increment based on DB max, not stored template only

After each incident save, query existing titles with the same prefix
to find the real max number, then use max(dbMax, tplNum) + 1.
Prevents duplicate counters when incidents were created before the
template was configured.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/db.ts

@@ -163,6 +163,20 @@ export async function deleteIncident(id: string): Promise<void> {
   await db.runAsync("DELETE FROM incidents WHERE id = ?", [id]);
 }
 
+export async function getMaxTitleNumber(prefix: string): Promise<number> {
+  const db = await getDb();
+  const rows = await db.getAllAsync<{ title: string }>(
+    "SELECT title FROM incidents WHERE title LIKE ?",
+    [`${prefix}%`]
+  );
+  let max = 0;
+  for (const row of rows) {
+    const n = parseInt(row.title.slice(prefix.length), 10);
+    if (!isNaN(n) && n > max) max = n;
+  }
+  return max;
+}
+
 export async function getDistinctServices(): Promise<string[]> {
   const db = await getDb();
   const rows = await db.getAllAsync<{ service: string }>(