fix: auto-rebuild better-sqlite3 for cross-platform npm installs (#129)

The npm package ships with better-sqlite3 compiled for Linux x64.
On Windows and macOS, the binary is incompatible and fails to load.

Added postinstall script that:
- Detects if the bundled native module is incompatible
- Automatically runs 'npm rebuild better-sqlite3' to compile for the target platform
- Provides manual fallback instructions if rebuild fails

scripts/postinstall.mjs

@@ -0,0 +1,57 @@
+#!/usr/bin/env node
+
+/**
+ * OmniRoute — Postinstall Native Module Rebuild
+ *
+ * The npm package ships with a Next.js standalone build that includes
+ * better-sqlite3 compiled for the build platform (Linux x64).
+ * This script detects platform mismatches and rebuilds the native
+ * module for the user's actual OS/architecture.
+ *
+ * Fixes: https://github.com/diegosouzapw/OmniRoute/issues/129
+ */
+
+import { execSync } from "node:child_process";
+import { existsSync } from "node:fs";
+import { join, dirname } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+const ROOT = join(__dirname, "..");
+
+// The standalone build bundles better-sqlite3 inside app/node_modules
+const appNodeModules = join(ROOT, "app", "node_modules", "better-sqlite3");
+
+if (!existsSync(appNodeModules)) {
+  // No bundled better-sqlite3 — nothing to do (dev install, not npm global)
+  process.exit(0);
+}
+
+const buildInfoPath = join(appNodeModules, "build", "Release", "better_sqlite3.node");
+
+// Quick check: try to load the native module
+try {
+  // Use a dynamic import-like approach — try to dlopen the .node file
+  process.dlopen({ exports: {} }, buildInfoPath);
+  // If it loaded, the binary is compatible — nothing to do
+  process.exit(0);
+} catch {
+  // Binary is incompatible — rebuild
+}
+
+console.log(`\n  🔧 Rebuilding better-sqlite3 for ${process.platform}-${process.arch}...`);
+
+try {
+  execSync("npm rebuild better-sqlite3", {
+    cwd: join(ROOT, "app"),
+    stdio: "inherit",
+    timeout: 120_000,
+  });
+  console.log("  ✅ Native module rebuilt successfully!\n");
+} catch (error) {
+  console.warn("  ⚠️  Failed to rebuild better-sqlite3 automatically.");
+  console.warn("     You can fix this manually by running:");
+  console.warn(`     cd ${join(ROOT, "app")} && npm rebuild better-sqlite3\n`);
+  // Don't fail the install — the user can fix manually
+}