feat(regen): Speak V2 TTS websocket, agent update-listen, Flux EOT tuning

[GregHolmes]

Summary

Fern SDK regeneration (2026-07-08). Pulls in new generator output, re-applies the hand-maintained patches, extends the socket-client convention to the new client, and adds test + example coverage for the new surface.

New public surface (Fern-generated this regen)

• Speak V2 — Flux TTS WebSocket (client.speak.v2.connect(...)): new speak/v2/ package (client, socket client, request/response types) plus top-level SpeakV2Encoding/MipOptOut/Model/SampleRate/Tag.
• Agent mid-session listen reconfigure: send_update_listen(...) with AgentV1UpdateListen/AgentV1UpdateListenListen, and the AgentV1ListenUpdated server acknowledgement.
• Flux end-of-turn tuning fields on the listen providers: eot_threshold, eager_eot_threshold, eot_timeout_ms.

Manual-patch reconciliation

The generator caught up on none of the existing back-compat concerns, so all 25 frozen patches were re-applied (nothing dropped from .fernignore), preserving the new generator additions:

• Legacy alias re-exports merged back into the package __init__.py files (kept alongside the new SpeakV2* / AgentV1* entries).
• language_hint → language_hints migration shim re-added to the three listen-provider models (kept alongside the new eot_* fields).
• Agent socket client: _sanitize_numeric_types, broad except Exception, optional send_keep_alive (kept the new send_update_listen).
• listen/v1, listen/v2, speak/v1 socket clients, query_encoder bool coercion, agent_v1settings* back-compat, create-key alias + wire test — all restored.

Judgment call — listen/v2 send_configure shim: kept

The generator now emits complete ListenV2Configure/ListenV2ConfigureSuccess models, but adopting them changes the public signature (raw dict → model, typed responses) — a breaking change. The typing.Any shim is kept for this maintenance regen; typed-model adoption is deferred to a future major/minor.

New: Speak V2 socket-client patch

The newly generated speak/v2/socket_client.py was made consistent with the other four socket clients and frozen:

• Broad except Exception (preserves the custom-transport error contract — a transport can raise arbitrary types; the narrow generated catch would leak them past the message loop).
• Optional send_flush() / send_close() for no-payload control messages (parity with speak/v1).

Test & example coverage

• tests/custom/test_speak_v2_socket.py — send serialization, response-type parsing, broad-except error emission.
• tests/custom/test_eot_thresholds_feature.py — eot_* fields serialize on all three listen providers.
• tests/custom/test_agent_update_listen.py — send_update_listen serialization + AgentV1ListenUpdated resolution.
• tests/manual/speak/v2/connect/ — standalone scripts (main / async / with_auth_token / with_raw_response), parity with speak/v1.
• examples/25-text-to-speech-streaming-v2.py (+ examples/README.md entry).
• reference.md — new "Speak V2 Connect" section and send_update_listen added to the Agent V1 send methods.

Verification

• mypy src/ — clean (844 files)
• mypy tests/typecheck — clean
• pytest — 318 passed, 1 skipped
• ruff check src — clean (new test/example/manual files add no new warnings)

Known limitation

Live end-to-end testing of Speak V2 is deferred: /v2/speak (Flux) currently returns HTTP 400 at the handshake, consistent with the endpoint not yet being publicly available / enabled. The SDK builds the correct, spec-conformant request (verified), and the unit tests validate client behavior without the live endpoint. The manual scripts are ready for the live check once Flux is enabled.