fix(anr): extend main thread detection from thread dump (#5733)

* fix(anr): detect main thread when OS names it after the process

On some Android versions/OEMs, AppExitInfo's thread dump names the
main thread after the process name (e.g. 'com.example.app') instead
of 'main'. ThreadDumpParser previously only matched on 'main',
causing the thread to not be flagged as main/crashed and resulting
in ANR events with no usable stack trace.

Pass the process name from ApplicationExitInfo.getProcessName() to
ThreadDumpParser and treat a thread as main if its name equals
'main' OR the process name.

Fixes JAVA-635

Co-Authored-By: sentry-junior[bot] <264270552+sentry-junior[bot]@users.noreply.github.com>

* Format code

* ref(anr): Detect main thread via sysTid matching process id

The main thread can be renamed by the OS to the (potentially truncated) process
name, so relying on the process name is fragile. On Linux/Android the main
thread's kernel thread id (sysTid) always equals the process id, so use that as
the authoritative signal instead.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* changelog

* Simplify changelog entry

* ref(anr): Normalize main thread name and skip threads without a stacktrace

Normalize the main thread's name back to "main" once it is identified (the OS
may have renamed it to the process name), and drop threads that have no
stacktrace as they are not actionable.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* ref(anr): Detect main thread via sysTid and skip stackless threads

Identify the main thread by matching the thread whose kernel thread id (sysTid)
equals the process id, falling back to the conventional "main" thread name, and
skip threads that have no stacktrace as they are not actionable.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* ref(anr): Clean up ThreadDumpParser

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Update CHANGELOG.md

Co-authored-by: Roman Zavarnitsyn <rom4ek93@gmail.com>

---------

Co-authored-by: sentry-junior[bot] <264270552+sentry-junior[bot]@users.noreply.github.com>
Co-authored-by: Sentry Github Bot <bot+github-bot@sentry.io>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-authored-by: Roman Zavarnitsyn <rom4ek93@gmail.com>