Add node dialog: the acting-for-an-org path still reads as a dead end

Seen while checking Task 8045 on a live stack (operator, `/nodes?add=1&org=<Org B>`, 1280px and 390px). 1. Jaah Cloud's radio stays drawn as disabled (a dashed ring, greyed title) even when it is the operator's way on, with "Act as <org>" under it. Draw it as a card that leads to a step, not as an unavailable one. 2. The "Act as <org>" button under Jaah Cloud is a small outlined button with low contrast on the dark card, easy to miss. Make it as visible as the dialog's other primary next step. 3. "<Org> Cloud" says "Runs in your AWS account. AWS bills you." even when the operator is filing for another org. Say whose account it is (that org's). Out of scope: later steps of Add node; the Brains row layout. Done means: - Each item shipped or declined with a one-line reason in the PR, with web unit tests where behaviour changed. - Screenshots at 1280px and 390px of each changed surface. Required checks: ./dc check full

Add node: Jaah Cloud now leads to its step, Act as is a primary button, and the AWS way names the org (title, copy, Configure). 3/3 shipped; quick gate and web tests green; visual check at 1280/390 done. PR #6295 queued to lane. Follow-up draft #8075.