Fix pglite-socket maxConnections JSDoc default (1, not 100)

[bahoo]

Tiny one: fixes a stale JSDoc in pglite-socket. The doc on PGLiteSocketServerOptions.maxConnections claims (default: 100), but the constructor actually defaults to 1. Three nearby spots agree the real default is 1:

• src/index.ts:572 — this.maxConnections = options.maxConnections ?? 1
• src/scripts/server.ts:67 — CLI flag default: '1'
• src/scripts/server.ts:94 — help text --max-connections=N ... (default is no concurrency: 1)

#902 later locked in the same wording across the README, so 1 is clearly the intended story — the JSDoc just needs to be brought up to speed, too. And both the docstring and the runtime default went in together in #873, so this is a same-PR typo rather than drift over time.

To reproduce:

const s = new PGLiteSocketServer({ db, path: '/tmp/foo' })
console.log(s.getStats().maxConnections) // → 1, not 100

Hope it saves the next person a head-scratch.