Let a super admin read the database from the app

A new super admin settings page, /admin/settings/database, lists every
table with its record count and size, and one page of the open table's
records newest key first. Values are cut inside SQL (400 characters, with
a flag saying so) and a record opens whole in a modal, so a table of long
texts reads without shipping it all. A search matches every column's
text, word by word or as a phrase, which is the one thing that also works
on a virtual table. Nothing in it writes: the catalog, the records and
the single record are all reads, GET only.

src/functions/backend/database/build-database-tables.ts

@@ -0,0 +1,59 @@
+import BunSQLite from "@moduletrace/bun-sqlite";
+import quoteSqlIdentifier from "./quote-sql-identifier";
+import resolveTableKey from "./resolve-table-key";
+import type { DatabaseTableSummary } from "@/src/types";
+import type { TableCatalogEntry } from "./table-catalog-types";
+
+type Params = {
+    tables: TableCatalogEntry[];
+    /**
+     * How many bytes each table takes on disk, by name; empty when SQLite
+     * can't measure it, which leaves the size column blank.
+     */
+    sizes: Map<string, number>;
+};
+
+type CountRow = { rows: number };
+
+/**
+ * The catalog as the browser lists it: every table with its record count,
+ * its size on disk, its columns and what identifies its records.
+ *
+ * Each count is its own tiny statement rather than one aggregate, because
+ * a virtual table has no rowid to build one from, and the whole read stays
+ * in the low milliseconds for the install's fifty-odd tables.
+ */
+export default async function buildDatabaseTables({ tables, sizes }: Params): Promise<DatabaseTableSummary[]> {
+    const summaries: DatabaseTableSummary[] = [];
+
+    for (const table of tables) {
+        const size = sizes.get(table.name);
+
+        summaries.push({
+            name: table.name,
+            type: table.type,
+            rows: await countRows({ table: table.name }),
+            size_bytes: size === undefined ? null : size,
+            columns: table.columns,
+            key: resolveTableKey({ columns: table.columns, has_rowid: table.has_rowid }),
+        });
+    }
+
+    return summaries;
+}
+
+async function countRows({ table }: { table: string }): Promise<number | null> {
+    const res = await BunSQLite.sql<CountRow>({
+        sql: `SELECT COUNT(*) AS rows FROM ${quoteSqlIdentifier({ name: table })}`,
+    });
+
+    if (!res.success || !res.payload?.[0]) {
+        /**
+         * A table the module won't count (an index over a table whose
+         * module is missing) is still a table; it just has no count.
+         */
+        return null;
+    }
+
+    return Number(res.payload[0].rows) || 0;
+}