feat(learner): package scaffold, auth tables migration, migrations runner

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/feature-learner/src/server/migrate.ts

@@ -0,0 +1,33 @@
+import { readdirSync, readFileSync } from "node:fs";
+import { join } from "node:path";
+import type { Db } from "@stc/db";
+
+/** Folders holding this package's migrations; Phase 2 wires these into `migrate()`. */
+export const migrationsDirs: string[] = [join(import.meta.dir, "..", "..", "migrations")];
+
+function statements(text: string): string[] {
+  const noComments = text.split("\n").filter((l) => !l.trim().startsWith("--")).join("\n");
+  return noComments.split(";").map((s) => s.trim()).filter(Boolean);
+}
+
+/**
+ * Applies the learner migrations with the same bookkeeping as `@stc/db`'s `migrate()`
+ * (table `schema_migrations`, keyed by file name). Safe to call repeatedly.
+ */
+export async function runMigrations(db: Db, dirs: string[] = migrationsDirs): Promise<string[]> {
+  await db.sql.unsafe("CREATE TABLE IF NOT EXISTS schema_migrations (name TEXT PRIMARY KEY, applied_at TEXT NOT NULL)");
+  const done = new Set((await db.sql`SELECT name FROM schema_migrations`).map((r: { name: string }) => r.name));
+  const applied: string[] = [];
+  for (const dir of dirs) {
+    for (const name of readdirSync(dir).filter((f) => f.endsWith(".sql")).sort()) {
+      if (done.has(name)) continue;
+      const stmts = statements(readFileSync(join(dir, name), "utf8"));
+      await db.sql.begin(async (tx) => {
+        for (const s of stmts) await tx.unsafe(s);
+        await tx`INSERT INTO schema_migrations (name, applied_at) VALUES (${name}, ${new Date().toISOString()})`;
+      });
+      applied.push(name);
+    }
+  }
+  return applied;
+}