feat: add export/import to the postgres backend; import auto-detects backend

The export/import plan predated the postgres backend. Bring it up to parity:

- PostgresInterface implements Exportable + Importable, mirroring the sqlite
  backend. Export is a signal-checked async generator (one query per table);
  import drives a transaction via `WrappedPool.multi`, which rolls back on any
  error/abort and commits only after the whole stream is consumed cleanly.
- The `note` kind is skipped on postgres (its note CRUD is still unimplemented,
  so a pg database holds none) — a full dump from sqlite imports its
  user/abode/resident/apikey records and drops notes.
- Unlike sqlite (PRAGMA foreign_keys=off), postgres keeps FK enforcement; the
  FK-safe insertion order keeps a full dump valid, and truly-dangling partial
  dumps will (correctly) fail.
- abode-import now resolves the backend via getDbInterface instead of
  constructing SqliteInterface directly; isImportable keeps it from ever
  running over the remote (api) interface, which has no import.
- Add isImportable(); make postgres selectClientApikeys' where optional.
- Tests: exercise the real PostgresInterface export/import paths against an
  in-memory fake WrappedPgClient (no pg service in CI) — NDJSON shape,
  meta.source, filtering, note-skip, insert dispatch, and error/abort rollback.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

test/backends/postgres/export-import.test.ts

@@ -0,0 +1,296 @@
+import { describe, it } from "node:test";
+import assert from "node:assert/strict";
+import { Readable } from "node:stream";
+import { PostgresInterface } from "../../../src/db/postgres/PostgresInterface.js";
+import type { WrappedPgClient } from "../../../src/db/postgres/pool.js";
+import type { SqlCode } from "../../../src/db/postgres/sql.js";
+
+// The postgres backend has no CI database, so these tests drive the real
+// PostgresInterface.export/import code paths against an in-memory fake client.
+// They verify control flow (NDJSON shape, meta.source, filtering, note
+// skipping, counts, insert dispatch, abort -> rollback); the SQL-arg forms are
+// the same {uuid}/{text}/{jsonb}/{date} patterns the pg backend's own CRUD
+// already exercises against real Postgres.
+
+interface Rows {
+  users?: Record<string, unknown>[];
+  abodes?: Record<string, unknown>[];
+  residents?: Record<string, unknown>[];
+  apikeys?: Record<string, unknown>[];
+}
+
+class FakePg implements WrappedPgClient {
+  readonly = false;
+  inserts: { table: string; vars: unknown[] }[] = [];
+  committed = false;
+  rolledBack = false;
+  #rows: Rows;
+
+  constructor(rows: Rows = {}) {
+    this.#rows = rows;
+  }
+
+  async destroy(): Promise<void> {}
+
+  async all<R>(stmt: SqlCode): Promise<R[]> {
+    const s = stmt._sql;
+    if (s.includes('FROM "users"')) return (this.#rows.users ?? []) as R[];
+    if (s.includes('FROM "abodes"')) return (this.#rows.abodes ?? []) as R[];
+    if (s.includes('FROM "residents"'))
+      return (this.#rows.residents ?? []) as R[];
+    if (s.includes('FROM "apikeys"')) return (this.#rows.apikeys ?? []) as R[];
+    return [] as R[];
+  }
+
+  async get<R>(stmt: SqlCode): Promise<R | null> {
+    const rows = await this.all<R>(stmt);
+    return rows[0] ?? null;
+  }
+
+  async run(stmt: SqlCode): Promise<{ changes: number }> {
+    const table = stmt._sql.match(/INSERT INTO "(\w+)"/)?.[1] ?? "?";
+    this.inserts.push({ table, vars: stmt._vars });
+    return { changes: 1 };
+  }
+
+  async multi<R>(fn: (tx: WrappedPgClient) => Promise<R>): Promise<R> {
+    try {
+      const r = await fn(this);
+      this.committed = true;
+      return r;
+    } catch (e) {
+      this.rolledBack = true;
+      throw e;
+    }
+  }
+
+  async rethrow<R>(fn: () => Promise<R>): Promise<R> {
+    return fn();
+  }
+}
+
+const iso = "2026-01-02T03:04:05.000Z";
+
+function seededRows(): Rows {
+  return {
+    users: [
+      {
+        uid: "11111111-1111-1111-1111-111111111111",
+        email: "u1@test.example",
+        name: "User One",
+        flags: {},
+        created_at: new Date(iso),
+        updated_at: new Date(iso),
+      },
+    ],
+    abodes: [
+      {
+        aid: "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaa1",
+        name: "Abode One",
+        created_at: new Date(iso),
+        created_by: "11111111-1111-1111-1111-111111111111",
+        updated_at: new Date(iso),
+        updated_by: null,
+      },
+      {
+        aid: "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaa2",
+        name: "Abode Two",
+        created_at: new Date(iso),
+        created_by: null,
+        updated_at: new Date(iso),
+        updated_by: null,
+      },
+    ],
+    residents: [
+      {
+        uid: "11111111-1111-1111-1111-111111111111",
+        aid: "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaa1",
+        flags: {},
+        created_at: new Date(iso),
+        created_by: null,
+        updated_at: new Date(iso),
+        updated_by: null,
+      },
+    ],
+    apikeys: [
+      {
+        uid: "11111111-1111-1111-1111-111111111111",
+        kid: "kkkkkkkk-kkkk-kkkk-kkkk-kkkkkkkkkkk1",
+        name: "key one",
+        permissions: {},
+        created_at: new Date(iso),
+        expires_at: null,
+      },
+    ],
+  };
+}
+
+async function streamToString(s: NodeJS.ReadableStream): Promise<string> {
+  let out = "";
+  for await (const chunk of s) out += chunk;
+  return out;
+}
+function parseLines(ndjson: string): { kind: string; data: any }[] {
+  return ndjson
+    .split("\n")
+    .filter(Boolean)
+    .map((l) => JSON.parse(l));
+}
+function line(kind: string, data: unknown): string {
+  return JSON.stringify({ kind, data }) + "\n";
+}
+
+describe("postgres export", () => {
+  it("streams meta + the four supported kinds, never note", async () => {
+    const db = new PostgresInterface(new FakePg(seededRows()));
+    const lines = parseLines(await streamToString(db.export()));
+
+    const meta = lines.find((l) => l.kind === "meta");
+    assert.ok(meta);
+    assert.equal(meta!.data.source, "postgres");
+    assert.equal(meta!.data.v, 1);
+
+    const kinds = new Set(lines.map((l) => l.kind));
+    assert.ok(kinds.has("user"));
+    assert.ok(kinds.has("abode"));
+    assert.ok(kinds.has("resident"));
+    assert.ok(kinds.has("apikey"));
+    assert.ok(!kinds.has("note"), "note is unsupported on postgres");
+  });
+
+  it("applies the kinds filter", async () => {
+    const db = new PostgresInterface(new FakePg(seededRows()));
+    const lines = parseLines(
+      await streamToString(db.export({ filter: { kinds: ["abode"] } })),
+    );
+    const kinds = new Set(
+      lines.filter((l) => l.kind !== "meta").map((l) => l.kind),
+    );
+    assert.deepEqual(kinds, new Set(["abode"]));
+  });
+
+  it("applies the abodes allowlist to abode/resident records", async () => {
+    const db = new PostgresInterface(new FakePg(seededRows()));
+    const lines = parseLines(
+      await streamToString(
+        db.export({
+          filter: { abodes: ["aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaa1"] },
+        }),
+      ),
+    );
+    const abodeAids = lines
+      .filter((l) => l.kind === "abode")
+      .map((l) => l.data.aid);
+    assert.deepEqual(abodeAids, ["aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaa1"]);
+  });
+});
+
+describe("postgres import", () => {
+  it("dispatches inserts per kind, skips note, and commits", async () => {
+    const fake = new FakePg();
+    const db = new PostgresInterface(fake);
+    const source = Readable.from([
+      line("meta", { v: 1 }),
+      line("user", {
+        uid: "11111111-1111-1111-1111-111111111111",
+        email: "u1@test.example",
+        name: "User One",
+        flags: {},
+        created_at: iso,
+        updated_at: iso,
+      }),
+      line("abode", {
+        aid: "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaa1",
+        name: "Abode One",
+        created_at: iso,
+        created_by: "11111111-1111-1111-1111-111111111111",
+        updated_at: iso,
+        updated_by: null,
+      }),
+      line("apikey", {
+        uid: "11111111-1111-1111-1111-111111111111",
+        kid: "kkkkkkkk-kkkk-kkkk-kkkk-kkkkkkkkkkk1",
+        name: "key one",
+        permissions: {},
+        created_at: iso,
+        expires_at: null,
+      }),
+      // note lines are silently skipped on postgres
+      line("note", {
+        nid: "nnnnnnnn-nnnn-nnnn-nnnn-nnnnnnnnnnn1",
+        aid: "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaa1",
+        name: "Note",
+        content: "x",
+        properties: {},
+        created_at: iso,
+        created_by: null,
+        updated_at: iso,
+        updated_by: null,
+      }),
+    ]);
+
+    const result = await db.import(source);
+    assert.deepEqual(result.counts, { user: 1, abode: 1, apikey: 1 });
+    assert.ok(fake.committed);
+    assert.deepEqual(fake.inserts.map((i) => i.table).sort(), [
+      "abodes",
+      "apikeys",
+      "users",
+    ]);
+    assert.ok(!fake.inserts.some((i) => i.table === "notes"), "no note insert");
+    // apikey gets a freshly-minted token (never exported)
+    const apikeyInsert = fake.inserts.find((i) => i.table === "apikeys")!;
+    assert.ok(
+      apikeyInsert.vars.some(
+        (v) => typeof v === "string" && v.startsWith("at_"),
+      ),
+      "apikey insert carries a fresh token",
+    );
+  });
+
+  it("rejects and rolls back when the stream carries an error sentinel", async () => {
+    const fake = new FakePg();
+    const db = new PostgresInterface(fake);
+    const source = Readable.from([
+      line("meta", { v: 1 }),
+      line("user", {
+        uid: "11111111-1111-1111-1111-111111111111",
+        email: "u1@test.example",
+        name: "User One",
+        flags: {},
+        created_at: iso,
+        updated_at: iso,
+      }),
+      line("error", { message: "boom" }),
+    ]);
+
+    await assert.rejects(() => db.import(source), /boom/);
+    assert.ok(fake.rolledBack);
+    assert.ok(!fake.committed);
+  });
+
+  it("rejects and rolls back on signal abort", async () => {
+    const fake = new FakePg();
+    const db = new PostgresInterface(fake);
+    const ac = new AbortController();
+    const source = Readable.from(
+      (async function* () {
+        yield line("meta", { v: 1 });
+        yield line("user", {
+          uid: "11111111-1111-1111-1111-111111111111",
+          email: "u1@test.example",
+          name: "User One",
+          flags: {},
+          created_at: iso,
+          updated_at: iso,
+        });
+        ac.abort();
+        await new Promise((r) => setTimeout(r, 1000));
+      })(),
+    );
+
+    await assert.rejects(() => db.import(source, { signal: ac.signal }));
+    assert.ok(fake.rolledBack);
+    assert.ok(!fake.committed);
+  });
+});