Fix STT language configuration and dialer lifecycle

[ivan-digital]

Summary

• fail fast when Parakeet receives a fixed language or any backend receives unsupported languageHints, with actionable Chinese locale guidance
• validate Nemotron prompt locales in JNI and document zh-CN / zh-TW as the Chinese path
• correct the Parakeet TDT v3 language count from 114 to 25 European languages across every README translation
• defer call and dial intents until Pocket TTS has drained, preventing Activity teardown from closing playback mid-response
• recover unexpected control-agent turn failures and cover deferred dial behavior with unit tests

Fixes #74.

This also addresses the call/dial execution failure reported in the S23 Ultra discussion.

Compatibility and risk

SpeechConfig now rejects settings that were previously silently ignored. Existing Parakeet integrations using a concrete language or non-empty languageHints must remove those settings or select NEMOTRON_MULTILINGUAL for prompt-conditioned recognition.

Call actions still use Android ACTION_DIAL; the app does not place calls directly and adds no permissions, network access, or data handling.

Test plan

• ./gradlew :sdk:test
• ./gradlew :sdk:assembleDebug
• ./gradlew :control-demo:testDebugUnitTest
• ./gradlew :control-demo:assembleDebug
• ./gradlew :control-demo:assembleRelease
• arm64 Android 15 emulator: reproduced the original dial/TTS overlap, verified TTS drains before the tel:123 dialer intent, returned to the app, and completed a second volume command

The full :sdk:connectedAndroidTest suite was not run; the targeted arm64 control-demo flow above exercised the Android lifecycle regression with real on-device models.