audio: add generic external route validation

[Srikanth Muppandam (smuppand)]

Summary

• add generic runtime-discovered playback validation for HDMI, DisplayPort/eDP, and 3.5 mm headphone routes
• add wired headset-microphone capture validation without falling back to an internal microphone
• add shared bounded ALSA route discovery, explicit mixer/PCM/device overrides, deterministic playback signal generation, strict recording validation, and mixer restoration
• keep the existing generic AudioPlayback and AudioRecord behavior unchanged

CI and fixture behavior

• route suites are opt-in and reusable across SoCs without fixed card or PCM numbers
• automatic discovery rejects ambiguous mappings and asks for exact CI overrides
• HDMI, DP/eDP, and headphone playback require fixture-side signal detection
• headset-microphone capture requires fixture-side audio injection
• missing optional image-provided ALSA utilities produce a clean skip and no packages are installed at runtime

Validation

• ShellCheck 0.9.0
• dash -n
• YAML parsing
• result-name and file-mode checks
• git diff --check
• mocked unique and ambiguous route discovery
• mocked timeout classification and mixer apply/restore paths
• mocked playback and headset-microphone recording flows
• strict RMS validation through the reduced-dependency od/dd fallback

Target validation still required

• HDMI playback with a connected audio-capable display
• DP/eDP playback with the corresponding fixture
• 3.5 mm headphone playback
• headset-microphone capture with an injected signal
• direct ALSA behavior on desktop distributions where PipeWire may own the device

[Srikanth Muppandam (smuppand)]

Bhargav-qcom (@bhargav0610) Need help on this PR in validation?

[Bhargav-qcom (bhargav0610)]

Anil (@qcom-anilyada) once done with validations pls update here

[Anil (qcom-anilyada)]

Anil (Anil (@qcom-anilyada)) once done with validations pls update here

validated on glymur (monaco-evk device doesn't have 3.5mm jack) with headphones in 3.5mm jack, it is skipping
scripts tested:

1. Runner/suites/Multimedia/Audio/AudioRoutePlayback/AudioRoutePlayback_Headphones.yaml
   • the requested headphones route was not visible in the PCM inventory
2. Runner/suites/Multimedia/Audio/AudioRouteRecord/AudioRouteRecord_HeadsetMic.yaml
   • the requested headset microphone was not visible in the capture PCM inventory
3. Runner/suites/Multimedia/Audio/AudioRoutePlayback/AudioRoutePlayback_DisplayPort.yaml
   • the requested displayport route was not visible in the PCM inventory

• https://lava.infra.foundries.io/scheduler/job/462688 (1+2)
• https://lava.infra.foundries.io/scheduler/job/462718 (3)