fix: jfrog oauth username extraction from oauth jwt token

[DevelopmentCats]

Description

Add username extraction from jfrog JWT OAuth token with fallback to coder username.

Type of Change

• New module
• New template
• Bug fix
• Feature/enhancement
• Documentation
• Other

Module Information

Path: registry/coder/modules/jfrog-oauth
New version: v1.2.2
Breaking change: [ ] Yes [X] No

Template Information

Path: registry/[namespace]/templates/[template-name]

Testing & Validation

• Tests pass (bun test)
• Code formatted (bun fmt)
• Changes tested locally

Related Issues

[Copilot]

Pull Request Overview

This PR fixes username extraction from JFrog OAuth JWT tokens to preserve special characters that Coder normalizes in usernames (dots, hyphens, accented characters). The implementation adds JWT payload parsing with a fallback to the existing username_field logic.

Key changes:

• Added JWT token parsing via data.external resource to extract username from OAuth token payload
• Updated username resolution logic to prioritize JWT-extracted username with fallback to Coder username/email
• Added documentation explaining the new username handling priority order

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
registry/coder/modules/jfrog-oauth/main.tf	Implements JWT username extraction using bash script in data.external resource and updates username resolution logic with coalesce for proper fallback handling
registry/coder/modules/jfrog-oauth/README.md	Documents the new username handling behavior, explaining JWT extraction priority and fallback mechanism

[Copilot]

Pull Request Overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

[matifali]

Assuming this has been tested.

[matifali]

LGTM.