Task page and node page UI polish

Seen while verifying Task 8564 on a local stack: 1. On the node page Overview at desktop width, the "Held" field wraps to three lines in its narrow grid cell. Give it a full-width row when it holds a sentence. 2. The "Blocked by" banner ends with "— not dispatch-ready until it is done and merged". Cut it to the facts (the linked tasks); the state chip already says the task is waiting. 3. The node-wait banner can't offer "Add node" to an operator viewing another org's task, because `/api/org/setup` only answers for the viewer's own org. Expose whether the task's org has a node on the task payload so every viewer gets the right action. 4. In the Answer tab at 390 px, the disabled "Comment only" and the quiet Attach have the same grey outline, so the enabled Attach reads as disabled. Give enabled Attach a visible, quiet difference. Out of scope: the behaviour shipped in Task 8564. Done means: - Each item shipped with a test, or rejected with a one-line reason in the PR. - Screenshots at 390 px and desktop.

Shipped all 4: Held full row, Blocked-by facts only, TaskOut.org_has_node (Add node for any viewer), grounded live Attach — each tested. Quick gate green; review lanes clean after fix; visual check 390px+desktop good. PR #6508 queued. Draft #8652 filed. Memory: none applied.