[Enhancement] Add first-class Bun runtime support with native WebSocket handling

[deepgram-robot]

Summary

Add proper Bun runtime detection and native WebSocket handling so that Deepgram's JS SDK works correctly in Bun without workarounds, warnings, or silent failures — matching the first-class support already provided for Node.js and browser environments.

Problem it solves

Multiple open issues report problems running the SDK in Bun (#466: WebSocket connection fails silently, #401: repeated "Using WS Package" logging). Bun is one of the fastest-growing JavaScript runtimes and is increasingly used for server-side applications where speech-to-text is common. Currently, developers using Bun must apply workarounds or fall back to Node.js, which undermines Bun's performance benefits. Since Bun has a native WebSocket implementation that differs from both Node.js and browser WebSocket APIs, the SDK needs explicit Bun detection and appropriate WebSocket selection.

Proposed API

// No API change needed — Bun support should be transparent
import { createClient } from "@deepgram/sdk";

const deepgram = createClient(DEEPGRAM_API_KEY);

// These should "just work" in Bun without warnings or fallbacks
const live = deepgram.listen.live({ model: "nova-3" });
const agent = deepgram.agent.live({ model: "nova-3" });

Internal changes:

• getGlobalWebSocket() should detect Bun runtime and use Bun's native WebSocket
• Remove spurious "Using WS Package" warnings when running in Bun
• Ensure WebSocket.send() binary handling matches Bun's implementation
• Add Bun to the CI test matrix

Acceptance criteria

• SDK initializes without warnings in Bun runtime
• Live STT WebSocket connections work correctly in Bun
• Voice Agent WebSocket connections work correctly in Bun
• TTS WebSocket connections work correctly in Bun
• No "Using WS Package" logging when running in Bun
• Documented with Bun-specific notes in README
• Compatible with existing API (no breaking changes)

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Raised by the DX intelligence system.