If you've tried to build a Salesforce integration lately, you've probably hit this wall. Connected Apps are being phased out. On new orgs in Winter '26, creating them in the UI is off by default, and starting Spring '26 you can't turn that option back on unless Salesforce Support approves it. So everyone is getting pushed toward External Client Apps (ECA), and the OAuth setup around them is genuinely confusing the first time you do it. The two-account Dev Hub plus namespace dance for a packaged ...