fix(db): keep SQLite temp files in memory so trips can be deleted (#2518)

Deleting a trip failed with SQLITE_IOERR_GETTEMPPATH when the container
runs with a read-only root filesystem and no tmpfs on /tmp. The cascade
behind DELETE FROM trips keeps a statement journal, SQLite moves it to a
temp file once it passes 64 KiB, and it looks for a directory for that
file in SQLITE_TMPDIR, TMPDIR, /var/tmp, /usr/tmp, /tmp and the working
directory. None of them is writable there. Installs on the shipped
compose file have a tmpfs on /tmp and never hit it.

Every connection the server opens now comes from openDatabase() in
src/db/connection.ts, which sets temp_store = MEMORY: the main database
(also when it is reopened after a restore), each plugin's own database
and the uploaded backup checked before a restore. reset-admin.js and the
key rotation script cannot import src/ in the image, so they set the
pragma themselves. A test pins that nothing else in src/ constructs a
handle, and one deletes a full trip on the real schema and watches for
temp files.

server/src/nest/plugins/host/plugin-data.service.ts

@@ -1,7 +1,7 @@
 import fs from 'node:fs';
 import path from 'node:path';
-import Database from 'better-sqlite3';
 import type { Database as Db } from 'better-sqlite3';
+import { openDatabase } from '../../../db/connection';
 import { pluginDataDir, pluginDbFile, pluginsDataRoot } from '../paths';
 
 /**
@@ -63,7 +63,7 @@ export class PluginDataDb {
   constructor(pluginId: string) {
     this.pluginId = pluginId;
     fs.mkdirSync(pluginDataDir(pluginId), { recursive: true });
-    this.db = new Database(pluginDbFile(pluginId));
+    this.db = openDatabase(pluginDbFile(pluginId));
     this.db.pragma('journal_mode = WAL');
     this.db.pragma('foreign_keys = ON');
     openDbs.add(this);