Add Global and Repository-Specific Environment Variables and Image Override Settings

[vedranjukic]

Feature Request

Overview

Implement a settings system for defining environment variables and container configurations that can be applied globally or per-repository when creating new projects.

Current State

• Project creation dialog has buttons for environment variables and image override
• These need to be manually configured for each new project

Requested Features

1. Global Settings

• Add a general settings section for defining default environment variables
• These should be preset for every new project in the project creation dialog
• Should also support default snapshot and container image override settings

2. Repository-Specific Settings

• Add ability to define specific settings for individual GitHub repositories
• Settings should include:
  • Environment variables
  • Snapshot configuration
  • Container image override
• When a GitHub repo URL (or issue/PR URL) is pasted in the project creation dialog, these repository-specific settings should be automatically applied
• Repository-specific settings should append to and override global settings

Implementation Notes

• Repository matching should work with:
  • Direct GitHub repository URLs
  • GitHub issue URLs
  • GitHub PR URLs
• Settings precedence: Repository-specific > Global defaults
• Environment variables should merge (repository-specific can add new vars or override global ones)
• Image overrides should completely replace global defaults when specified at repository level

User Experience

1. User configures global defaults in settings
2. User configures repository-specific overrides in settings
3. When creating a new project with a GitHub URL, both sets of settings are automatically applied
4. User can still manually modify settings in the project creation dialog before creating the project

Acceptance Criteria

• Global settings UI for default env vars, snapshot, and image override
• Repository-specific settings UI with GitHub repo input
• Automatic detection and application of settings in project creation dialog
• Proper merging/override logic for settings precedence
• Settings persistence and management (add/edit/delete repository configs)