[BENCH-622] Add Deepdub TTS provider

[coval-cale]

Streams dd-etts-3.0 over Deepdub's realtime WebSocket API as an early-access entry with a preset voice pool.

Greptile Summary

Adds Deepdub's dd-etts-3.0 TTS integration as an early-access model using its realtime WebSocket API.

• Adds Deepdub API-key configuration and provider registry wiring.
• Implements PCM streaming, error handling, TTFA timing, and WAV result finalization.
• Registers a two-voice preset pool and adds provider-level tests.

Confidence Score: 4/5

The premature-close path should be fixed before merging because it can silently record truncated Deepdub synthesis as valid benchmark data.

The provider recognizes isFinished inside the loop but does not require that signal after iteration ends, while downstream finalization and orchestration treat any nonempty audible PCM without an error as a successful measurement.

Files Needing Attention: runner/src/coval_bench/providers/tts/deepdub.py

_{Reviews (1): Last reviewed commit: "[BENCH-622] Add Deepdub TTS provider" | Re-trigger Greptile}

Greptile also left 1 inline comment on this PR.

Context used:

• Knowledge Base — Runner Orchestration

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Project	Deployment	Actions	Updated (UTC)
benchmarks	Ready	Preview	Aug 5, 2026 7:33pm

[coderabbitai]

Walkthrough

Added Deepdub API-key configuration and provider registry entries. Added DeepdubTTSProvider with model and voice validation, realtime WebSocket synthesis, PCM decoding, timing, diagnostics, error handling, and 24 kHz audio metadata. Added a Deepdub model registry entry and provider tests.

Suggested reviewers: borgesius, callumreid

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 18.75% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the primary change: adding the Deepdub TTS provider.
Description check	✅ Passed	The description accurately summarizes the Deepdub TTS integration, configuration, streaming behavior, model registration, and tests.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@runner/src/coval_bench/providers/tts/deepdub.py`:
- Around line 94-117: Update the send and receive flow in
DeepdubTTSProvider.synthesize so the WebSocket operation is bounded by the
provider’s request timeout, including waiting for each frame until isFinished.
Catch the timeout, then return a failed TTSResult through the existing failure
path instead of waiting indefinitely; preserve normal audio collection and
completion behavior.

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Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 6fa4608f-3b62-4cba-ab35-438a759a8220

📥 Commits

Reviewing files that changed from the base of the PR and between 1fc0a4a and 73df716.

📒 Files selected for processing (7)

• .env.example
• runner/src/coval_bench/config.py
• runner/src/coval_bench/providers/tts/__init__.py
• runner/src/coval_bench/providers/tts/deepdub.py
• runner/src/coval_bench/registries/models.py
• runner/src/coval_bench/registries/provider_keys.py
• runner/tests/providers/tts/test_deepdub.py

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In @.env.example:
- Line 42: Replace the FLUXIONS_API_KEY entry in the environment template with
DEEPDUB_API_KEY=, matching the configuration and provider-key symbols used by
config.py and provider_keys.py.

🪄 Autofix

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 27918c05-db0f-4d7e-b00a-941c68effb7e

📥 Commits

Reviewing files that changed from the base of the PR and between 73df716 and c27d026.

📒 Files selected for processing (6)

• .env.example
• runner/src/coval_bench/config.py
• runner/src/coval_bench/providers/tts/deepdub.py
• runner/src/coval_bench/registries/models.py
• runner/src/coval_bench/registries/provider_keys.py
• runner/tests/providers/tts/test_deepdub.py

🚧 Files skipped from review as they are similar to previous changes (4)

• runner/src/coval_bench/config.py
• runner/src/coval_bench/registries/provider_keys.py
• runner/src/coval_bench/registries/models.py
• runner/src/coval_bench/providers/tts/deepdub.py