chore(test): add matplotlib and plotly test case

[leavesster]

fix #257

add plotly and matplotlib preview

use block preview event to check plotly and matplotlib lib

[Copilot]

Pull Request Overview

This PR adds a matplotlib-based test case along with the supporting task and package configuration for the "plot" flow.

• Added a new test case in flow-examples/test/flow.test.ts to run and validate the plot flow.
• Introduced task configuration files and a Python task implementation to generate a basic matplotlib plot.
• Added a bootstrap script in the plot package configuration to set up dependencies.

Reviewed Changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
flow-examples/test/flow.test.ts	New test case for executing the plot flow and validating exit code.
flow-examples/packages/plot/tasks/show/task.oo.yaml	YAML configuration for the show task using matplotlib.
flow-examples/packages/plot/tasks/show/init.py	Python task implementation that generates and displays a plot.
flow-examples/packages/plot/package.oo.yaml	Package configuration with bootstrap script for dependency setup.
flow-examples/flows/plot/flow.oo.yaml	Flow definition that includes the new plot task.

Files not reviewed (1)

• flow-examples/packages/plot/requirements.txt: Language not supported

Comments suppressed due to low confidence (2)

flow-examples/test/flow.test.ts:98

• It is recommended to assert that the result of events.find is not undefined to ensure the 'BlockPreview' event is actually emitted.

events.find(e => e.event === "BlockPreview");

flow-examples/packages/plot/tasks/show/init.py:16

• Using plt.show() in a non-interactive or headless test environment may block execution; consider using an alternative backend or saving the plot to a file.

plt.show()