refactor: replace Prisma ORM runtime with Drizzle ORM facade

- Replace Prisma client runtime with Drizzle ORM (zero Prisma engine/query engine in production)
- Add Prisma-compatible facade (@/lib/prisma-facade.ts) backed by Drizzle for backwards compatibility
- Runtime queries route through Drizzle ORM; @prisma/client is now devDependency (types only)
- Remove @prisma/adapter-mariadb dependency; delete prisma-pool.ts and types/prisma.ts
- New Drizzle schema layer: src/db/schema.ts (176 tables) and src/lib/db.ts (connection)
- Update README documenting the dual-layer ORM architecture
- Restore src/generated/ gitignore (build artifact for local type generation)
- 0 TypeScript errors, 583 tests passing

The facade intentionally uses `any` types to match the Prisma Client API surface,
allowing existing code to run unmodified while routing queries through Drizzle at runtime.

src/app/admin/permissions/page.tsx

@@ -1,7 +1,7 @@
+import { sql } from "drizzle-orm";
 import { redirect } from "next/navigation";
-import { Prisma } from "@/generated/prisma/client";
+import { db } from "@/lib/db";
 import { canAccess, getAdminContext, PERMS } from "@/lib/permissions";
-import { prisma } from "@/lib/prisma";
 import { fetchEmulatorRankSummaries } from "@/lib/services/permission-ranks";
 import { PermissionsList } from "./permissions-list";
 
@@ -19,12 +19,12 @@ export default async function PermissionsPage({
 	const sp = (await searchParams) ?? {};
 	const fromHousekeeping = sp.from === "housekeeping";
 
-	const ranks = await fetchEmulatorRankSummaries(prisma);
+	const ranks = await fetchEmulatorRankSummaries(db);
 
 	// User counts per rank
-	const rawCounts: { rank: number; cnt: number }[] = await prisma.$queryRaw(
-		Prisma.sql`SELECT \`rank\`, COUNT(*) as cnt FROM users GROUP BY \`rank\``,
-	);
+	const [rawCounts] = (await db.execute(
+		sql`SELECT \`rank\`, COUNT(*) as cnt FROM users GROUP BY \`rank\``,
+	)) as unknown as [{ rank: number; cnt: number }[], unknown[]];
 	const countMap: Record<number, number> = {};
 	for (const row of rawCounts) {
 		countMap[Number(row.rank)] = Number(row.cnt);