Add opt-in slow SQL and database diagnostics

scripts/database-diagnostics.mjs

@@ -0,0 +1,16 @@
+import Database from 'better-sqlite3';
+import { statSync } from 'node:fs';
+
+const path = process.argv[2] ?? process.env.DB_PATH ?? './data/cherry.db';
+const db = new Database(path, { readonly: true, fileMustExist: true });
+try {
+    console.table(['', '-wal', '-shm'].map(suffix => {
+        try { return { file: path + suffix, bytes: statSync(path + suffix).size }; }
+        catch (error) { if (error.code !== 'ENOENT') throw error; return { file: path + suffix, bytes: 0 }; }
+    }));
+    console.table(db.prepare(`SELECT name, ROUND(SUM(pgsize)/1048576.0, 2) AS mib
+        FROM dbstat GROUP BY name ORDER BY SUM(pgsize) DESC LIMIT 20`).all());
+    console.table(['page_size', 'page_count', 'freelist_count', 'auto_vacuum'].map(pragma => ({
+        pragma, value: db.pragma(pragma, { simple: true })
+    })));
+} finally { db.close(); }