ci: add changelog section for performance improvements

[jusiskin]

What was the problem/requirement? (What/Why)

There is no development/release workflow for communicating performance improvements.

What was the solution? (How)

Conventional commits standardizes the perf: ... commit type for this purpose.

This followed a previous work in aws-deadline/deadline-cloud#870:

1. adds a section to the changelog template for performance improvements
2. adds perf commits to the patch_tags setting of python-semantic-release so that they are considered as part of bumping a version for release
3. adds developer-facing documentation for using the perf: commit type for performance improvements

What is the impact of this change?

Developers can use perf: ... conventional commits to communicate performance improvements. The release process will automatically produce a changelog section for performance improvements where they will be listed.

How was this change tested?

1. Set my local mainline branch to this commit
2. Added example commits using the perf: ... commit summary message
3. Ran:

   hatch run release:deps
   hatch run release:bump
   

4. confirmed that rendered CHANGELOG.md contained the expected "Performance Improvements" section correctly

0.7.3 (2025-10-24)

Performance Improvements

• a performance improvement (03dfa78)

Was this change documented?

Yes. I added documentation for the perf: commit type to CONTRIBUTING.md.

Is this a breaking change?

No

Does this change impact security?

No

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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