fix: Profiling memory leak in std::thread

[indragiek]

📜 Description

This is a follow up to #3055 that fixes the final memory leak reported in #2980

std::thread appears to have some kind of bug (or maybe we were using it incorrectly, but I don't understand how) that causes it to not free the parameters that were passed to the thread entry function. In this PR we switch to using the pthread APIs directly and managing memory manually, which fixes the leak.

💚 How did you test it?

Verified with Instruments that the leak no longer reproduces:

📝 Checklist

You have to check all boxes before merging:

• I reviewed the submitted code.
• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.

🔮 Next steps

[codecov]

Codecov Report

Merging #3061 (af09a4d) into main (98752f3) will decrease coverage by 0.013%.
The diff coverage is 85.294%.

Additional details and impacted files

@@              Coverage Diff              @@
##              main     #3061       +/-   ##
=============================================
- Coverage   88.859%   88.846%   -0.013%     
=============================================
  Files          492       492               
  Lines        52994     53024       +30     
  Branches     18983     18997       +14     
=============================================
+ Hits         47090     47110       +20     
- Misses        4950      4955        +5     
- Partials       954       959        +5     

Impacted Files	Coverage Δ
Sources/Sentry/SentrySamplingProfiler.cpp	79.279% <85.294%> (-2.165%)	⬇️

... and 7 files with indirect coverage changes

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[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1249.76 ms	1273.67 ms	23.92 ms
Size	20.76 KiB	434.62 KiB	413.86 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
c021422	1199.15 ms	1222.20 ms	23.05 ms
d40512b	1231.12 ms	1244.54 ms	13.42 ms
3f366ee	1244.49 ms	1257.28 ms	12.79 ms
b2f82fa	1237.78 ms	1256.02 ms	18.24 ms
8f397a7	1230.10 ms	1253.88 ms	23.77 ms
98a8c16	1206.40 ms	1232.14 ms	25.74 ms
a6f8b18	1236.96 ms	1240.14 ms	3.18 ms
7bc3c0d	1259.74 ms	1268.45 ms	8.71 ms
7e8d5fd	1208.69 ms	1228.14 ms	19.45 ms
cd3bfeb	1226.61 ms	1226.96 ms	0.35 ms

App size

Revision	Plain	With Sentry	Diff
c021422	20.76 KiB	435.64 KiB	414.88 KiB
d40512b	20.76 KiB	427.77 KiB	407.00 KiB
3f366ee	20.76 KiB	427.84 KiB	407.08 KiB
b2f82fa	20.76 KiB	419.62 KiB	398.86 KiB
8f397a7	20.76 KiB	420.55 KiB	399.79 KiB
98a8c16	20.76 KiB	431.00 KiB	410.24 KiB
a6f8b18	20.76 KiB	431.87 KiB	411.11 KiB
7bc3c0d	20.76 KiB	427.35 KiB	406.59 KiB
7e8d5fd	20.76 KiB	435.50 KiB	414.74 KiB
cd3bfeb	20.76 KiB	425.77 KiB	405.01 KiB

Previous results on branch: indragiek/fix-last-leak

Startup times

Revision	Plain	With Sentry	Diff
c731cab	1238.06 ms	1249.82 ms	11.76 ms

App size

Revision	Plain	With Sentry	Diff
c731cab	20.76 KiB	434.56 KiB	413.80 KiB

[brustolin]

LGTM