fix: route Speak V2 websocket through custom transport_factory

[mayankbohradev]

Summary

A transport_factory passed to DeepgramClient or AsyncDeepgramClient was not applied to the Speak V2 WebSocket client. Speak V2 connected through the default websockets transport instead, with no error or warning.

Who this affects

transport_factory exists so callers can route WebSocket traffic through their own transport, including proxies, test doubles, and custom-hosted endpoints. Before this fix, Listen v1/v2, Speak v1, and Agent v1 used the custom transport while Speak V2 silently connected directly to api.deepgram.com.

This is especially important for callers relying on controlled network egress, auditing, or custom-hosted transports: accepting the factory but bypassing it can send traffic to an unintended endpoint without any signal.

Root cause

install_transport() patches the generated modules listed in _TARGET_MODULES in src/deepgram/transport.py. Speak V2 shipped after that hand-maintained list was created, and deepgram.speak.v2.raw_client and deepgram.speak.v2.client were never added.

The existing tests iterated _TARGET_MODULES itself, so they could verify registered modules were patched but could not detect a real WebSocket module missing from the list.

Changes

• add deepgram.speak.v2.raw_client and deepgram.speak.v2.client to _TARGET_MODULES
• add an independent source scan that fails when a generated WebSocket module is absent from the registry
• add a non-vacuous guard proving discovery finds a known WebSocket module
• document the _TARGET_MODULES regeneration invariant in AGENTS.md
• update the stale module count and apply the configured import ordering

The guard intentionally uses a static source scan rather than pkgutil.walk_packages to avoid import side effects and still detect modules that fail to import. It asserts a subset rather than exact equality because the runtime registry may intentionally contain a module not present in a particular generated tree; the behavior-breaking case is a real WebSocket module absent from the registry.

Verification

• confirmed the new guard fails on the unpatched tree and names both missing Speak V2 modules
• no-network runtime probe confirmed both sync and async speak.v2.connect() invoke the supplied factory with the expected /v2/speak URL and authorization headers
• full Docker-backed suite: 380 passed, 1 skipped
• focused transport suite: 36 passed
• mypy src/: clean across 882 source files
• Ruff import-order check and src/deepgram/transport.py check: clean
• git diff --check: clean
• warning count unchanged: two existing websockets deprecation warnings