feat: F5.1 server F keeps the shared documents

A new package, packages/server: Hocuspocus 3.4.4 on /sync, a project a
document, refused with a reason when the store has not got it; every update
stored in Postgres as it comes and compacted after 500 updates, a minute of
quiet and when the last person leaves (FOR UPDATE on the row written when
the project is made); the janitor runs only here, at loading and 250 ms
after a change that is not its own; readers change nothing; /healthz; JSON
log. On closing it takes no one new and closes the sockets too (Hocuspocus'
close is a message after which a client signs in again on the same socket).
The tests use real clients against a throwaway Postgres in Docker.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/server/test/database.ts

@@ -0,0 +1,42 @@
+// A Postgres of its own for the server's tests: FILIUS_TEST_DATABASE_URL
+// when it is set, else a throwaway container of the postgres image (Docker),
+// stopped and gone after the tests. Never a database of the dashboard.
+
+import { execFileSync } from 'node:child_process';
+import pg from 'pg';
+
+export interface TestDatabase {
+  readonly url: string;
+  stop(): Promise<void>;
+}
+
+export async function testDatabase(): Promise<TestDatabase> {
+  const given = process.env.FILIUS_TEST_DATABASE_URL;
+  if (given !== undefined) return { url: given, stop: async () => {} };
+  const name = `filius-test-pg-${process.pid}-${Date.now()}`;
+  execFileSync('docker', ['run', '-d', '--rm', '--name', name, '-e', 'POSTGRES_PASSWORD=filius', '-e', 'POSTGRES_DB=filius', '-p', '127.0.0.1::5432', 'postgres:16-alpine'], { stdio: 'pipe' });
+  const stop = async () => {
+    execFileSync('docker', ['stop', name], { stdio: 'pipe' });
+  };
+  try {
+    const port = execFileSync('docker', ['port', name, '5432/tcp']).toString().trim().split('\n')[0]!.split(':').pop();
+    const url = `postgres://postgres:filius@127.0.0.1:${port}/filius`;
+    // The image's first start runs a server on its socket only; the TCP port answers once the real one is up.
+    for (let tries = 0; ; tries++) {
+      const client = new pg.Client({ connectionString: url });
+      try {
+        await client.connect();
+        await client.query('SELECT 1');
+        await client.end();
+        return { url, stop };
+      } catch (error) {
+        await client.end().catch(() => {});
+        if (tries > 120) throw error;
+        await new Promise((resolve) => setTimeout(resolve, 250));
+      }
+    }
+  } catch (error) {
+    await stop();
+    throw error;
+  }
+}