VPAAMP-919:additional low latency-specific VPA metrics

[varshnie]

Reason for change:Added target latency as part of playbackProgressUpdate
Risks: p1

[Copilot]

Pull request overview

This PR extends AAMP’s progress update / ProgressEvent pipeline to expose the latency monitor’s target latency as an additional low-latency-specific metric (surfaced through the JS bindings for VPA telemetry).

Changes:

• Add mTargetLatency to ProgressEvent, with constructor parameter + getter.
• Populate targetLatency in PrivateInstanceAAMP::MonitorProgress() and include it in progress logging.
• Expose targetLatency on the JS progress-update event object in both JS listener implementations.

Scores: Completeness 8/10, Assumptions 7/10, Clarity 8/10, CostRisk 4/10 | Critique: Clear diffs and intent, but lacks explicit unit/activation semantics and doesn’t show test updates for the API change. | Improve: Add “units (ms) + when it is 0” and “updated utests/fakes” to the PR description.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
priv_aamp.cpp	Computes target latency from the latency monitor and adds it to ProgressEvent + progress log output.
AampEvent.h	Extends ProgressEvent with mTargetLatency, constructor parameter, and a getter declaration.
AampEvent.cpp	Wires mTargetLatency through the constructor and implements getTargetLatency().
jsbindings/jseventlistener.cpp	Adds targetLatency property to the JS progress-update event.
jsbindings/jsbindings.cpp	Adds targetLatency property to the JS progress-update event (alternate listener path).

Suppressed comments (1)

AampEvent.h:807

• Changing ProgressEvent's constructor signature requires updating the unit-test fake and tests that define/call this constructor (e.g., test/utests/fakes/FakeAampEvent.cpp and test/utests/tests/AampEventTests/AampEventTests.cpp). As-is, this will break the utest build and also leaves the fake without a getTargetLatency() implementation if anything links against it.

	ProgressEvent(double duration, double position, double start, double end, float speed, long long pts, double videoBufferedDuration, double audioBufferedDuration, std::string seiTimecode, double liveLatency, double targetLatency, BitsPerSecond profileBandwidth, BitsPerSecond networkBandwidth, double currentPlayRate, std::string sid);