Allow connection profiles to be declared in workspace settings.json for team sharing

Empieza rastreando la activación de la extensión y cómo se cargan las conexiones en el árbol de conexiones; después, inspecciona las rutas existentes de almacenamiento de secretos y de configuración del usuario. Define cómo se fusionan los descriptores del workspace con las conexiones personales, cómo se muestra el badge de origen y cómo una contraseña ausente llega al prompt normal. Se considera terminado cuando los perfiles de workspace no secretos aparecen después de clonar sin hacer commit de las credenciales, y las conexiones personales existentes siguen funcionando.

Problem

Connection profiles in the PostgreSQL extension are stored in VS Code's global secret storage and user settings — neither of which is committed to source control. In a team environment, every developer must manually re-enter connection details (host, port, database, username) for shared databases (dev/staging). There is no way to ship a pre-populated, non-secret connection profile as part of a repository.

Use Case

A team wants to commit a .vscode/settings.json that pre-declares non-secret connection attributes:

{
  "pgsql.connections": [
    {
      "name": "Dev DB (shared)",
      "host": "dev-db.internal.example.com",
      "port": 5432,
      "database": "myapp_dev",
      "user": "devuser",
      "passwordSource": "prompt" // or "pgpass" | "secretStorage"
    }
  ]
}

When a developer clones the repo and opens it, the connection appears pre-populated in the sidebar — they only need to supply the password.

Why This Is Safe

Passwords are never committed (the passwordSource field controls where the credential comes from). Only non-secret metadata (host, port, db name, user) is in the settings file. This mirrors how SQL Server extension (mssql) handles workspace-level connection profiles.

Proposed Change

1. Add pgsql.connections as a workspace-scope configuration key (array of connection descriptors, no password field).
2. On activation, merge connections from workspace settings into the connections tree (alongside secret-storage ones), displaying a source badge ("workspace" vs "personal").
3. Connecting a workspace connection that has no password triggers the normal password prompt and optionally stores it in secret storage for the session.

Environment

• VS Code: 1.89+, team sharing .vscode/settings.json via git
• Extension: ms-ossdata.vscode-pgsql latest