* Modernize ddev create check template to Python 3.13 idioms

- Replace Python 2-style super() call with bare super().__init__()
- Replace PEP 484 comment-form type annotations with inline annotations
- Add typed signatures to check() and __init__() using InitConfigType and
  InstanceType from datadog_checks.base.types
- Type conftest fixtures (Iterator[None], InstanceType)
- Remove noqa: F401 markers that existed only to support comment annotations
- Use dict[str, Any] instead of Dict[str, Any] in test_unit.py

* Add changelog entry for PR #23705

* Shorter changelog

* Add ConfigMixin and bump datadog-checks-base version in template

* Enable mypy in check template via hatch check-types

Enable check-types in hatch.toml so mypy runs as part of ddev test --lint
on every new integration generated from the check template. Add
--explicit-package-bases to handle the namespace package layout under
datadog_checks/.

Fix the dd_run_check fixture annotation in test_unit.py from
Callable[[AgentCheck, bool], None] (which lied about the signature and
was previously hidden inside a PEP 484 comment) to Callable[..., None],
matching the actual fixture signature run_check(check, extract_message=
False, cancel=True).

* Add test_e2e template and teaching comments for tests

Add tests/test_e2e.py to the check template so new integrations ship
with an end-to-end test from day one. The stub is gated by
@pytest.mark.e2e so it does not run under `ddev test`, only under
`ddev env test`. Live assertions cover the metadata sanity checks
(assert_metrics_using_metadata + assert_all_metrics_covered); a
commented block lists the common per-metric, per-tag and service-check
assertions.

Expand tests/test_unit.py with the same teaching-comment pattern
already used in check.py: a commented menu of assert_metric,
assert_metric_has_tag, assert_metric_has_tag_prefix and
assert_service_check.

Add a commented docker_run + CheckEndpoints example to dd_environment
in tests/conftest.py so users see the canonical setup pattern without
shipping an empty docker/ folder, which would be misleading given how
divergent real integration setups are.

* Delete servicechecks comment

* Use find_free_port in conftest docker_run example

Address review feedback: replace the hardcoded port 1234 in the
commented dd_environment example with find_free_port(get_docker_hostname()),
so users following the pattern do not collide with whatever happens to
be listening on their host.

* Move self.config to check() and rename changelog

* Change comment

* Fix README template to align with current capitalization

* Capitalize 'Checks'

Co-authored-by: Ursula Chen <58821586+urseberry@users.noreply.github.com>

* Capitalize 'Collected'

Co-authored-by: Ursula Chen <58821586+urseberry@users.noreply.github.com>

* Remove --explicit-package-bases from hatch.toml template

* Capitalize Collected

Co-authored-by: Ursula Chen <58821586+urseberry@users.noreply.github.com>

* Capitalize Checks

Co-authored-by: Ursula Chen <58821586+urseberry@users.noreply.github.com>

---------

Co-authored-by: Ursula Chen <58821586+urseberry@users.noreply.github.com>