Add Python 3.12 and 3.13 support

[omertahaoztop]

What does this PR do, and why?

This PR adds support for Python 3.12 and Python 3.13.
These versions are now stable, and extending compatibility ensures the project remains installable and testable on current Python releases.
The changes update packaging metadata, CI configuration, and any version-specific compatibility checks where necessary.

Outstanding aspect(s)

• None

External discussion & connections

• Discussed in #zulip-terminal in topic
• Fully fixes #
• Partially fixes issue #
• Builds upon previous unmerged work in PR #
• Is a follow-up to work in PR #
• Requires merge of PR #
• Merge will enable work on #

How did you test this?

• Manually - Behavioral changes
• Manually - Visual changes
• Adapting existing automated tests
• Adding automated tests for new behavior (or missing tests)
• Existing automated tests should already cover this

Self-review checklist for each commit

• Commit is a minimal coherent idea
• Commit summary follows documented style
• Summary describes motivation & reasoning for the change
• Each commit passes linting and tests
• Contains test additions if new behavior is introduced
• Commit flow is logical and prepares for the next step

Visual changes