chore(github): add a release commit-type box to the PR template

[JarryShaw]

Please follow the guide below

• You will be asked some questions, please read them carefully and answer honestly

• Put an x into all the boxes [ ] relevant to your pull request (like that [x])

• Use Preview tab to see how your pull request will actually look like

• Searched for similar pull requests

• Followed the coding style (make pylint, make mypy, make isort) — not run; those targets cover pcapkit/ only and this touches no library code

• make test passes, and a test case covers the change — tests/project only, see below

• Added a changelog entry under docs/source/changelog/ and regenerated CHANGELOG.md, if the change is user-visible — N/A, added centrally after the wave

What is the purpose of your pull request?

Tick the commit type your subject line carries.

• fix — corrects a defect
• feat — adds a feature
• perf — changes performance, not behaviour
• refactor — changes neither behaviour nor performance
• test — tests only
• docs — documentation only
• ci — workflows or build tooling
• chore — anything else

---

Description of your pull request and other information

Closes #1102

• Adds - [ ] `release` — bumps the version or rolls up a distribution above chore, which stays last as the catch-all. CONTRIBUTING.md:202 only names the type, so the wording follows process.rst's release label row ("version bumps and distribution rollups").
• New tests/project/test_pr_template_commit_types_1102_unit.py checks that the template's boxes are exactly CONTRIBUTING.md's type list. Without the fix it fails (1 failed, release missing). With the fix it passes (1 passed).
• test_conventions_doc_claims.py: one docstring line said release had no tickbox, which is now false. Only the prose changed.
• pytest tests/project -q: 380 passed, 1 skipped, 1286 subtests passed.

[JarryShaw]

Cross-review verdict on 85e5a18ad: GOOD TO GO (reviewed on Sonnet; authored on Opus)

• The box: release sits above chore, so chore stays the catch-all. Its wording matches process.rst:209.
• The new test checks both directions. It fails when any of these is mutated:
  • the template is missing release;
  • the template has an extra box;
  • CONTRIBUTING.md lists an extra type.
• Guard: a parse that finds fewer than 9 types fails the test rather than passing vacuously.
• Docstring: the edit to test_conventions_doc_claims.py is accurate; only const lacks a box.
• Tests: tests/project passes, with 380 passed and 1 skipped.

[github-actions]

Coverage: 88.74% (unit tier, Python 3.14, 85e5a18ad, Unit Tests run success)

Package	Statements	Missed	Branches	Partial	Cover
pcapkit (top level)	104	4	20	4	93.55%
pcapkit/const	18757	1035	2342	846	90.23%
pcapkit/corekit	1874	91	578	22	94.33%
pcapkit/dumpkit	136	0	40	0	100.00%
pcapkit/foundation	2422	143	842	34	92.62%
pcapkit/interface	112	7	40	5	92.11%
pcapkit/protocols	15653	187	3942	162	98.19%
pcapkit/toolkit	487	71	144	3	84.15%
pcapkit/utilities	429	4	122	4	98.55%
pcapkit/vendor	4409	2359	1006	158	42.84%

Per-file detail: the coverage-html artifact of this run.