fix: add Final annotation to __version__ and document shutdown_cycles (#1059)

[microsasa]

Closes #1059

Changes

1. __version__ missing Final annotation

File: src/copilot_usage/__init__.py

Changed __version__: str → __version__: Final[str] per coding guidelines requiring Final for module-level constants that should never be reassigned. Final was already imported in the file.

2. SessionSummary.shutdown_cycles absent from implementation.md field table

File: src/copilot_usage/docs/implementation.md

Added the shutdown_cycles row to the SessionSummary fields table, documenting its type (list[tuple[datetime | None, SessionShutdownData]]) and how it's populated by build_session_summary().

3. Regression test for Final annotation

File: tests/test_packaging.py

Added test_version_is_final_str() which asserts that __version__ is annotated as Final[str] using typing.get_origin and typing.get_args, guarding against regression.

Warning

⚠️ Firewall blocked 2 domains

The following domains were blocked by the firewall during workflow execution:

• astral.sh
• pypi.org

To allow these domains, add them to the network.allowed list in your workflow frontmatter:

network:
  allowed:
    - defaults
    - "astral.sh"
    - "pypi.org"

See Network Configuration for more information.

Generated by Issue Implementer · ● 8.6M · ◷

[Copilot]

Pull request overview

This PR addresses two small code-health/documentation gaps in copilot_usage: it makes the public __version__ constant explicitly non-reassignable via Final[str], and documents the existing SessionSummary.shutdown_cycles field in the implementation guide. It also adds a regression test to prevent the annotation from being accidentally removed later.

Changes:

• Annotate copilot_usage.__version__ as Final[str].
• Document SessionSummary.shutdown_cycles in docs/implementation.md’s field table.
• Add a packaging regression test asserting the Final[str] annotation.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/copilot_usage/__init__.py	Updates __version__ typing to Final[str] to match constant conventions.
src/copilot_usage/docs/implementation.md	Adds missing shutdown_cycles entry to the SessionSummary fields table.
tests/test_packaging.py	Adds a regression test ensuring __version__ remains annotated as Final[str].

[github-actions]

Low-impact changes: Final type annotation on __version__, documentation gap fill for shutdown_cycles, and a meaningful regression test. All CI checks pass. Auto-approving for merge.