refactor(voice-engine): extract Gemini Live event loop into native_se…

[jjleng]

…ssion module

[jjleng]

@claude

[claude]

Claude finished @jjleng's task in 1m 4s —— View job

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Code Review

• Read CLAUDE.md for repo guidelines
• Read changed files and diff
• Analyze refactoring and provide review feedback

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The refactoring is clean and well-scoped — session.rs is now a proper thin coordinator as its doc comment says, and native_session.rs is a self-contained module with good doc comments (including the ASCII audio-path diagram). No regressions spotted. A few items worth addressing:

Minor Issues

Inconsistent tracing usage (native_session.rs:63)

The file imports error from tracing at the top:

use tracing::{error, info, warn};

But line 63 uses the fully qualified form instead of the imported one:

tracing::error!("[native] No Gemini API key ...");

Lines 102 and 481 correctly use the bare error!. This should be made consistent. Fix this →

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Inconsistent use of crate:: inline paths vs top-level imports (native_session.rs)

Types from agent_kit, voice_trace, etc. are all imported at the top, but several internal types use inline crate:: paths inside the function body:

• native_session.rs:79 — crate::utils::PlaybackTracker
• native_session.rs:114 — crate::utils::SAMPLE_RATE
• native_session.rs:118 — soxr::SoxrStreamResampler (used inline, not imported)
• native_session.rs:123 — crate::reactor::proc::vad::VadStage
• native_session.rs:124 — crate::audio_ml::vad::VadConfig
• native_session.rs:132 — crate::utils::AudioRingBuffer
• native_session.rs:185–186 — crate::audio_ml::vad::VAD_THRESHOLD_PLAYBACK_RAW / VAD_THRESHOLD_IDLE

These would read more clearly as top-level imports matching the rest of the file's style. Fix this →

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#[allow(clippy::too_many_arguments)] suppression (native_session.rs:41)

The function currently takes 13 arguments. This attribute suppresses the lint rather than addressing it. Since this is a refactor, it's a good opportunity to bundle the arguments into a struct (e.g., NativeSessionArgs or reusing an extended NativeMultimodalConfig). That said, this is pre-existing behavior, so it's fine to defer if this is out of scope for this PR.

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Nit

native_session.rs:88–96 — The greeting injection happens inside run_native_multimodal after SessionConfig::finalize() has already prepended any language instruction to system_prompt. The resulting prompt order is [language] + [original prompt] + [greeting], which seems intentional, but a brief comment noting that finalize() runs before this would make the ordering explicit to future readers.

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Overall: clean extraction, good module doc with audio-path diagram. The two style issues (tracing macro + inline crate paths) are the only things worth fixing before merge.