Fix PostgreSQL health check connection string parsing

[Copilot]

Why make this change?

PostgreSQL health checks fail with Keyword not supported: 'host' error. Direct assignment of connection strings to DbConnection.ConnectionString bypasses driver-specific parsing, causing Npgsql to reject lowercase keywords like host, port, database.

What is this change?

Normalize connection strings through database-specific builders before assignment:

• Added Utilities.NormalizeConnectionString(): Routes to NpgsqlConnectionStringBuilder for PostgreSQL, SqlConnectionStringBuilder for MSSQL/DWSQL, passthrough for others
• Updated HttpUtilities.ExecuteDbQueryAsync(): Accepts DatabaseType parameter, applies normalization before connection initialization
• Updated HealthCheckHelper.ExecuteDatasourceQueryCheckAsync(): Threads DatabaseType through call chain

This mirrors the pattern used in PostgreSqlExecutor, MsSqlQueryExecutor, and throughout the codebase for managed connection handling.

How was this tested?

• Integration Tests (existing health endpoint tests)
• Unit Tests

Sample Request(s)

GET /health HTTP/1.1
Host: localhost:5000

# Returns comprehensive health report with datasource check
# Previously failed with connection string parsing error for PostgreSQL

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[Bug]: Health check fails to check postgres data-source</issue_title>
<issue_description>## What

When the health check attempts to check a Postgres data-source, it gets an error.

</issue_description>

<agent_instructions>Fix this with as few lines of new code as possible.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

@JerryNixon # Solution

https://youtu.be/Js06lpu_YsM @ 5:00 time

#2797</comment_new>

• Fixes [Bug]: Health check fails to check postgres data-source #2796

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[Copilot]

Pull request overview

This PR fixes PostgreSQL health check failures caused by connection string parsing errors. The issue occurred when direct assignment to DbConnection.ConnectionString bypassed Npgsql's parser, causing it to reject lowercase connection string keywords like host, port, and database.

Changes:

• Added Utilities.NormalizeConnectionString() method to route connection strings through database-specific builders (NpgsqlConnectionStringBuilder for PostgreSQL, SqlConnectionStringBuilder for MSSQL/DWSQL)
• Updated HttpUtilities.ExecuteDbQueryAsync() to accept DatabaseType parameter and apply connection string normalization
• Threaded DatabaseType through HealthCheckHelper.ExecuteDatasourceQueryCheckAsync() to enable normalization

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/Service/HealthCheck/Utilities.cs	Added NormalizeConnectionString method to parse and normalize connection strings using database-specific builders
src/Service/HealthCheck/HttpUtilities.cs	Updated ExecuteDbQueryAsync to accept DatabaseType parameter and apply connection string normalization before creating database connection
src/Service/HealthCheck/HealthCheckHelper.cs	Updated ExecuteDatasourceQueryCheckAsync to pass DatabaseType parameter through to HttpUtilities for connection string normalization

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[Copilot]

The NormalizeConnectionString method should handle exceptions from the connection string builders. Throughout the codebase (e.g., PostgreSqlMetadataProvider.TryGetSchemaFromConnectionString at src/Core/Services/MetadataProviders/PostgreSqlMetadataProvider.cs:47-58, RuntimeConfigLoader.GetPgSqlConnectionStringWithApplicationName at src/Config/RuntimeConfigLoader.cs:416-427), connection string builder instantiation is wrapped in try-catch blocks to handle potential parsing errors. If a malformed connection string is passed here, the exception will propagate up and may not be handled appropriately in the health check context. Consider wrapping the builder instantiation in a try-catch block and either logging the error and returning the original connection string, or allowing the exception to propagate with proper context.

Suggested change

	switch (dbType)
	{
	case DatabaseType.PostgreSQL:
	return new NpgsqlConnectionStringBuilder(connectionString).ToString();
	case DatabaseType.MSSQL:
	case DatabaseType.DWSQL:
	return new SqlConnectionStringBuilder(connectionString).ToString();
	default:
	return connectionString;
	}
	try
	{
	switch (dbType)
	{
	case DatabaseType.PostgreSQL:
	return new NpgsqlConnectionStringBuilder(connectionString).ToString();
	case DatabaseType.MSSQL:
	case DatabaseType.DWSQL:
	return new SqlConnectionStringBuilder(connectionString).ToString();
	default:
	return connectionString;
	}
	}
	catch (Exception)
	{
	// If the connection string cannot be parsed by the builder,
	// return the original string to avoid failing the health check.
	return connectionString;
	}