fix(plotting): add show=True parameter to PlotMethods for blocking display in scripts

[tanishkasinghhh]

Problem

camelot.plot(table).show() calls matplotlib's Figure.show(), which
returns immediately in non-interactive (Agg / script) backends — the
window closes before the user can see it (issue #296).

The correct blocking entry point for scripts is plt.show(block=True).
However, Figure.show() does not accept a block argument, so users
cannot work around it without calling plt.show() separately — and this
is not obvious from the camelot API.

Fix

Add show=False to PlotMethods.__call__(). When show=True, call
plt.show(block=True) after creating the figure.

# Before — window closes immediately in scripts
fig = camelot.plot(tables[0], kind='grid')
fig.show()   # Figure.show(), non-blocking

# After — window stays open until the user closes it
fig = camelot.plot(tables[0], kind='grid', show=True)

The default is False to preserve existing behaviour for all callers
(Jupyter notebooks, image-comparison tests, file-save paths).

Changes

File	What
camelot/plotting.py	Add show=False kwarg; call plt.show(block=True) when set (only on non-filename paths)
tests/test_plot_show.py	4 unit tests: verify plt.show not called by default; called with block=True when requested; figure is still returned; save-to-file path unaffected

Tests

pytest tests/test_plot_show.py -v
# 4 passed — fails before fix (TypeError: unexpected keyword argument 'show')

Closes #296

Prepared with AI assistance (Claude Code). Every change reviewed and understood line-by-line.

[bosd]

Triage: the failing check here is pre-commit, not the test suite — all the tests jobs (3.10–3.14, Windows, macOS) pass. So the plotting change itself is fine; it's a lint/format gate.

Two things ruff flags in the new test file:

1. S108 (×2, unfixable auto) — Probable insecure usage of temporary file: "/tmp/out.png". Hardcoded /tmp/... paths trip flake8-bandit. Fix by using pytest's tmp_path fixture instead:

   def test_...(tmp_path):
       out = tmp_path / "out.png"
       ...
       mock_fig.savefig.assert_called_once_with(str(out))

2. ruff-format — one file needs reformatting; run pre-commit run --all-files (or ruff format) locally and commit.

pre-commit is a hard-required gate here, so once those two are addressed CI should go green. The show=True design itself looks reasonable for #296. Thanks for the contribution, @tanishkasinghhh!