feat(18-02): PATCH and DELETE handlers at /api/templates/[id]

- PATCH accepts name and signatureFields for rename and field save per D-10
- PATCH sets updatedAt: new Date() explicitly per D-05
- PATCH returns 404 for archived or missing templates
- DELETE soft-deletes by setting archivedAt: new Date() per D-07 (no hard delete)
- DELETE sets updatedAt: new Date() per D-05, returns 204 No Content
- Both handlers auth-gated with auth() per D-11

teressa-copeland-homes/src/app/api/templates/[id]/route.ts

@@ -0,0 +1,69 @@
+import { auth } from '@/lib/auth';
+import { db } from '@/lib/db';
+import { documentTemplates } from '@/lib/db/schema';
+import type { SignatureFieldData } from '@/lib/db/schema';
+import { and, eq, isNull } from 'drizzle-orm';
+
+export async function PATCH(
+  req: Request,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  const session = await auth();
+  if (!session) return new Response('Unauthorized', { status: 401 });
+
+  const { id } = await params;
+  const body = await req.json() as {
+    name?: string;
+    signatureFields?: SignatureFieldData[];
+  };
+
+  // Only update non-archived templates
+  const existing = await db.query.documentTemplates.findFirst({
+    where: and(eq(documentTemplates.id, id), isNull(documentTemplates.archivedAt)),
+  });
+  if (!existing) {
+    return Response.json({ error: 'Not found' }, { status: 404 });
+  }
+
+  const updates: Partial<typeof documentTemplates.$inferInsert> = {
+    updatedAt: new Date(),  // per D-05: explicit updatedAt on every UPDATE
+  };
+  if (body.name !== undefined) updates.name = body.name;
+  if (body.signatureFields !== undefined) updates.signatureFields = body.signatureFields;
+
+  const [updated] = await db
+    .update(documentTemplates)
+    .set(updates)
+    .where(eq(documentTemplates.id, id))
+    .returning();
+
+  return Response.json(updated);
+}
+
+export async function DELETE(
+  _req: Request,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  const session = await auth();
+  if (!session) return new Response('Unauthorized', { status: 401 });
+
+  const { id } = await params;
+
+  // Only soft-delete non-archived templates (idempotent)
+  const existing = await db.query.documentTemplates.findFirst({
+    where: and(eq(documentTemplates.id, id), isNull(documentTemplates.archivedAt)),
+  });
+  if (!existing) {
+    return Response.json({ error: 'Not found' }, { status: 404 });
+  }
+
+  await db
+    .update(documentTemplates)
+    .set({
+      archivedAt: new Date(),   // per D-07: soft-delete sets archivedAt
+      updatedAt: new Date(),    // per D-05: explicit updatedAt
+    })
+    .where(eq(documentTemplates.id, id));
+
+  return new Response(null, { status: 204 });
+}