Add support for Plex JWT Authentication

[JonnyWong16]

Description

Ref.: https://developer.plex.tv/pms/#section/API-Info/Authenticating-with-Plex

• Added new myplex.MyPlexJWTAuth class to handle Plex JWT authentication.
• Added new utils.plexJWTAuth() helper function for Plex JWT authentication.

Example using class:

from plexapi.myplex import MyPlexAccount, MyPlexJWTLogin

# Method 1: Generate a new Plex JWT using Plex OAuth
jwtlogin = MyPlexJWTLogin(
    oauth=True,
    scopes=['username', 'email', 'friendly_name']
)
jwtlogin.generateKeypair(keyfiles=('private.key', 'public.key'))
print(f'Login to Plex at the following url:\n{jwtlogin.oauthUrl()}')
jwtlogin.run()
jwtlogin.waitForLogin()
jwtToken = jwtlogin.jwtToken

account = MyPlexAccount(token=jwtToken)

# Method 2: Generate a new Plex JWT using an existing Plex token and keypair
jwtlogin = MyPlexJWTLogin(
    token='2ffLuB84dqLswk9skLos',
    keypair=('private.key', 'public.key'),
    scopes=['username', 'email', 'friendly_name']
)
jwtlogin.registerDevice()
jwtToken = jwtlogin.refreshJWT()

account = MyPlexAccount(token=jwtToken)

# Refresh an existing Plex JWT
jwtlogin = MyPlexJWTLogin(
    jwtToken=jwtToken,
    keypair=('private.key', 'public.key'),
    scopes=['username', 'email', 'friendly_name']
)
if not jwtlogin.verifyJWT():
    jwtToken = jwtlogin.refreshJWT()

account = MyPlexAccount(token=jwtToken)

Example using helper function:

from plexapi.utils import plexJWTAuth

# Generate a new Plex JWT using Plex OAuth
# Client identifier and keypair will be generated automatically
account = plexJWTAuth(scopes=['username', 'email', 'friendly_name'])

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated the docstring for new or existing methods
• I have added tests when applicable

[Copilot]

Pull Request Overview

This PR adds support for Plex JWT Authentication, implementing a new authentication method that uses JSON Web Tokens with ED25519 key pairs as described in the Plex API documentation.

Key changes include:

• Implementation of a new MyPlexJWTLogin class for handling JWT-based authentication flows (OAuth and token-based)
• Addition of plexJWTAuth() helper function for simplified JWT authentication using OAuth
• Support for ED25519 keypair generation, JWT encoding/decoding, and token refresh functionality

Reviewed Changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
requirements_dev.txt	Adds pyjwt[crypto] as a development dependency for JWT functionality
pyproject.toml	Adds optional 'jwt' dependency group for JWT authentication support
plexapi/utils.py	Adds JWT authentication helper functions, UUID generation, base64url encoding, and updates to existing OAuth functions for consistency
plexapi/myplex.py	Implements MyPlexJWTLogin class with JWT generation, verification, refresh, and device registration capabilities
README.rst	Documents the new JWT optional dependency installation

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}