VPAAMP-410 linear cdai race condition that can cause a required init segment to not be injected

[pstroffolino]

Reason for Change: Add INFO-level diagnostic logs at four key points in the CDAI
clear-to-encrypted ad-to-content transition path:

1. FetchAndInjectInitialization gate: log profileChanged and
   discontinuity per track before the init fetch condition is
   evaluated, to detect silent skip of init injection.

2. FetchAndInjectInitialization fetch: log the resolved init URL
   and discontinuity flag when the gate passes, to detect use of
   a wrong (clear/ad) init segment URL.

3. onAdEvent OUTSIDE_ADBREAK: log mCurrentPeriod, endPeriodId,
   endPeriodOffset and mCurrentPeriodIdx at the point mBasePeriodId
   is updated, to detect period index mismatch after ad completion.

4. SelectSourceOrAdPeriod exit: log periodChanged, adStateChanged
   and requireStreamSelection before returning, to confirm
   StreamSelection will run for the content period.

5. MediaStreamContext init cache: log HIT/MISS and URL for every
   init segment fetch, to detect stale cache entries returning
   a clear init segment for an encrypted period URL.

All new log lines use [CDAI-DBG] prefix for easy filtering.

When the soak test captures the failure, grep the INFO logs for [CDAI-DBG] around the timestamp of the crash. The sequence to look for in the bad case will be SelectSourceOrAdPeriod exit showing requireStreamSelection=0, followed immediately by FetchAndInjectInitialization showing profileChanged=0 discontinuity=0 for the video track — confirming the init fetch was silently skipped before the encrypted segments began flowing.

[Copilot]

Pull request overview

This PR primarily adds INFO-level diagnostic logging to help investigate a linear CDAI (clear ad → encrypted content) transition issue where init segments may not be injected. It also introduces additional changes around MP4 integrity monitoring, log-level locking behavior, and macOS dependency installation.

Changes:

• Add [CDAI-DBG] INFO logs at key CDAI transition points (init injection gate/fetch, ad state transitions, stream-selection decisions) and init-fragment cache HIT/MISS.
• Add an optional MP4 integrity monitor that parses downloaded audio/video segments with persistent Mp4Demux validators and dumps corrupt segments.
• Improve macOS install scripts to detect/install GStreamer pkg-config paths; comment out some noisy CLI/downloader logs.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
fragmentcollector_mpd.cpp	Adds [CDAI-DBG] logs for init injection gating/fetching, adbreak completion, and period/stream-selection decisions.
MediaStreamContext.cpp	Adds [CDAI-DBG] init-fragment cache HIT/MISS logging; short-circuits injection when eAAMPConfig_SuppressDecode is set.
priv_aamp.h	Adds CheckSegmentIntegrity() declaration and persistent Mp4Demux validator members; includes MP4Demux.h.
priv_aamp.cpp	Implements MP4 segment integrity checking and hooks it into GetFile() under config control; comments out a WARN log.
AampConfig.h	Adds eAAMPConfig_MonitorMp4Integrity boolean config.
AampConfig.cpp	Registers monitorMp4Integrity config key; changes ConfigureLogSettings() to lock log level for `"warn"
scripts/install_dependencies.sh	Adds macOS GStreamer framework/homebrew detection and installs via brew if missing.
scripts/install_aampcli.sh	Adds macOS GStreamer framework/homebrew pkg-config path discovery and clearer error on missing GStreamer.
downloader/AampCurlDownloader.cpp	Comments out a WARN log line related to network persona.
test/aampcli/Aampcli.cpp	Comments out manifest-refresh related CLI prints.

Comments suppressed due to low confidence (1)

test/aampcli/Aampcli.cpp:689

• Same issue here: leaving a commented-out AAMPCLI_PRINTF makes the intent unclear and risks bitrot. Prefer removing it entirely or controlling it via an explicit verbosity/log-level setting.

				default:
				{
					std::string manifest = mAampcli.mSingleton->GetManifest();
					//AAMPCLI_PRINTF("[AAMPCLI] Dash Manifest length [%zu]\n", manifest.length());
					break;