[WIP][crashtracking] Runtime stack collection callback registration

[gyuheon0h]

lol ignore the 53k line change...

What does this PR do?

Motivation:

Change log entry

Additional Notes:

How to test the change?

[github-actions]

👋 Hey @DataDog/ruby-guild, please fill "Change log entry" section in the pull request description.

If changes need to be present in CHANGELOG.md you can state it this way

**Change log entry**

Yes. A brief summary to be placed into the CHANGELOG.md

(possible answers Yes/Yep/Yeah)

Or you can opt out like that

**Change log entry**

None.

(possible answers No/Nope/None)

^{Visited at: 2025-10-20 21:14:21 UTC}

[github-actions]

Typing analysis

This PR does not change typing compared to the base branch.

[datadog-datadog-prod-us1]

⚠️ Tests

⚠️ Warnings

🧪 1 Test failed

gem release process datadog.gemspec files includes all important files from rspec (Datadog)

the missing elements were:      ["my-libdatadog-build/x86_64-linux/LICENSE", "my-libdatadog-build/x86_64-linux/LICENSE-3rdparty.yml",...uild/x86_64-linux/lib/pkgconfig/datadog_profiling_with_rpath.pc", "test_crashtracker_standalone.rb"]

Failure/Error:
  expect(gemspec.files)
    .to match_array(
      \`git ls-files -z\`
        .split("\x0")
        .reject { |f| f.match(directories_excluded) }
        .reject { |f| f.match(single_files_excluded) }
    )
...

ℹ️ Info

❄️ No new flaky tests detected

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 12f6ea8 | Docs | Was this helpful? Give us feedback!}

[gyuheon0h]

• [WIP][crashtracking] Runtime stack collection callback registration #4984 👈 (View in Graphite)
• master

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