feat(agentkit): add Engine v2.14 support to the Python SDK

[seymourtang]

Summary

Update the generated Python SDK and AgentKit layer to match the Engine v2.14 API, including RTZR speech recognition, the latest Sarvam TTS options, speak sentence-segmentation settings, and production Gemini TTS. Existing Gemini TTS preview integrations remain source-compatible while moving to the regional production gateway.

What Changed

• Updated generated RTZR ASR, speak, Deepgram, Sarvam, and Gemini TTS models for the Engine v2.14 contract.

• Added global-only RtzrSTT, generated aliases, and SpeakConfig/ParametersSpeak support for parameters.speak.batch.

• Updated SarvamTTSOptions with speech sample rate, preprocessing, model, flattened additional_params, and compatibility for the deprecated sample-rate alias.

• Aligned generated Deepgram credentials with asr.params.api_key and updated preset inference, legacy credential compatibility, vendor routing, and avatar sample-rate handling.

• Promoted Gemini TTS from preview to production routing. Synchronous and asynchronous GeminiTTS sessions and raw tts.vendor = "gemini" configurations use the configured regional endpoint for the complete lifecycle without agora-feature: gemini-live.

• Registered Gemini TTS in the production global vendor catalog while retaining package-root, agentkit.preview, and agentkit.preview.gemini_tts imports as aliases. The v2.11.0 model, defaults, validation, additional_params, and skip_patterns remain supported; named fields override passthrough values.

• Kept generated style optional. Historical preview calls that omit it continue to serialize without a style field.

• Updated AgentKit documentation, regional routing guidance, changelog entries, and regression coverage.

Testing

• Focused Gemini TTS, preview compatibility, and generated schema tests: 61 passed
• Full custom test suite: 456 passed, 1 skipped
• Coverage includes synchronous and asynchronous US/EU/AP production routing, raw configurations, complete lifecycle requests, catalog registration, preview import compatibility, additional-parameter precedence, and skip patterns.

Anam Avatar portrait options

• Promoted Engine 2.11+ Anam avatar_model, video_width, and video_height parameters to first-class AgentKit options.
• Supports Cara 4 portrait mode with cara_mk4; width and height must be supplied together (for example, 720x1280), or both may be omitted to keep the model default.
• Explicit options override matching additional_params values.

Additional validation

• Focused Anam, vendor, and session tests: 52 passed
• Ruff checks passed for changed implementation and test logic (excluding pre-existing import-order warnings)