[Feature Request]: Database Connection Environment Highlighting (Color Coding for Dev/Test/Prod)

### What would you like to happen?

Current Situation
Currently, all database connections in the Metadata Perspective look identical regardless of the environment they point to. Users must rely solely on the connection name to distinguish between Development, Homologation (HML), and Production environments. This increases the risk of accidental execution of pipelines or transformations against the wrong environment.

Proposed Improvement
Add an optional "Environment Color" property to the Database Connection metadata.

Color Selection: Within the Database Connection dialog, allow users to pick a color (e.g., Green for Dev, Yellow for HML, Red for Prod).

UI Integration: * The connection name in the Metadata tree should have a background or foreground highlight with the selected color.

Ideally, when a pipeline using a "Red" (Production) connection is open, a small border or indicator could appear in the canvas to warn the user.

Expected Behavior
A user can quickly identify that postgres_data_warehouse is a Production server because it is highlighted in red in the sidebar, while oracle_morrihos_organize_hml is highlighted in green, as shown in the provided mockup.

Screenshots / Mockups

### Issue Priority

Priority: 3

### Issue Component

Component: Metadata

The issue identifies the Metadata Perspective, Database Connection dialog, metadata tree, and pipeline canvas, but names no files or tests. Start by locating the entry points for database-connection metadata and its tree rendering, then define the supported color property and warning behavior; done means environment colors are visible where specified and covered by tests.

Written by the indexing model from the issue text.