Pytest matrix runs a single interpreter; binding it exposes a macOS/3.11 hatch env failure

## Summary

`.github/workflows/pytest.yaml` declares a 15-cell test matrix, but every cell runs the same interpreter, so the repo currently has **no real Python version coverage**. Fixing that reveals a second, separate problem: `hatch env create dev` fails on `macos-latest` + Python 3.11.

Raised by Copilot review on #155; removed from that PR to keep it scoped to dependency patching.

## 1. The matrix does not test what it claims

```yaml
strategy:
matrix:
os: [ubuntu-latest, macos-latest, windows-latest]
python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
steps:
- name: Set up Python
uses: actions/setup-python@v7
with:
python-version: '3.x' # <-- not bound to the matrix
```

`python-version` is hardcoded, so all 15 jobs install the newest available CPython. The job names (`pytest (ubuntu-latest, 3.10)`) claim coverage the run does not provide. `requires-python = ">=3.10"`, so 3.10–3.13 are effectively untested.

The one-line fix is `python-version: ${{ matrix.python-version }}`.

## 2. That fix exposes a macOS + 3.11 environment failure

With the binding applied, `pytest (macos-latest, 3.11)` fails during **Install dependencies**:

```
Syncing environment plugin requirements
Environment `dev` has unknown type: pip-compile
##[error]Process completed with exit code 1.
```

Notes:

- Reproducible across **two independent runner allocations** (initial run and `gh run rerun --failed`).
- The plugin sync completes in ~240 ms and installs nothing before the failure.
- `pip-compile` comes from `hatch-pip-compile`, declared in `[tool.hatch.env] requires`. The error means the plugin was not loaded, not that the dev dependencies are wrong.
- **Not reproducible locally.** On macOS arm64 with CPython 3.11.14, against a clean `main` worktree, `hatch env create dev` exits 0 and `hatch run dev:pytest` gives 76 passed / 100% coverage. Same result on the #155 branch.
- Other cells in the same run get past this step (`ubuntu-latest, 3.10` ran the full suite green before fail-fast cancelled it).

So this looks like a hosted-runner-specific hatch plugin resolution problem, not a dependency or source defect.

## 3. Fail-fast hides the picture

`strategy` has no `fail-fast: false`, so the single macOS/3.11 failure cancelled the other 14 jobs mid-step. Adding `fail-fast: false` alongside the matrix fix would show the true per-version state in one run instead of one failure at a time.

## Suggested order of work

1. Add `fail-fast: false`.
2. Bind `python-version: ${{ matrix.python-version }}`.
3. Triage the resulting failures; investigate the macOS/3.11 `hatch env create dev` failure (likely pinning `hatch`/`hatch-pip-compile`, or installing the plugin explicitly before `hatch env create`).

## Evidence

- Failing job: https://github.com/github/annotated-logger/actions/runs/31826048213/job/94850326975
- Reverted from #155 in `8818bb0`; the binding itself is `91eac8c`.

Start with .github/workflows/pytest.yaml and inspect the matrix, Python setup step, and fail-fast behavior. Run the workflow to confirm that each matrix cell uses its declared interpreter and capture the macOS/3.11 hatch environment result. Done means the matrix reports genuine version coverage, fail-fast no longer hides cells, and the hosted environment failure is resolved or clearly isolated.

Written by the indexing model from the issue text.