FN-6154: let the mobile node editor fill the screen

Let the mobile workflow node editor inspector use the full available height.

- remove the mobile inspector max-height cap so the editor stage can expand full screen
- update the WorkflowNodeEditor mobile CSS contract test to assert the new max-height rule
- quarantine the unrelated flaky dashboard Board test and record it in the quarantine ledger

Files changed:
 packages/dashboard/app/components/WorkflowNodeEditor.css          | 1 +
 .../app/components/__tests__/WorkflowNodeEditor.css.test.ts       | 1 +
 packages/dashboard/vitest.config.ts                               | 2 +-
 scripts/lib/test-quarantine.json                                  | 8 +++++++-
 4 files changed, 10 insertions(+), 2 deletions(-)

Fusion-Task-Id: FN-6154

Fusion-Task-Lineage: 14928ad1-dc84-461b-9adf-b5ee079e3b0d

scripts/lib/test-quarantine.json

@@ -1,4 +1,10 @@
 {
   "$comment": "Flaky-test quarantine ledger (deletion ratchet — see AGENTS.md 'Flaky tests: quarantine on sight' and docs/testing.md 'Quarantine ledger and the deletion ratchet'). A test observed failing without a corresponding real bug is quarantined ON SIGHT: add an entry here AND a matching one-line `exclude` entry in that package's vitest config, in the same commit. Every entry needs a non-empty `reason` (link the failing run) and a `quarantinedAt` date — the entry expires 14 days later, at which point the test file is DELETED unless someone rescues it with evidence it catches real regressions plus a root-cause fix (never appeasement). There is deliberately no loader module and no automation around this file: it is a dated record, the vitest config exclude is the mechanism, and the sweep is policy executed by whoever touches the suite.",
-  "entries": []
+  "entries": [
+    {
+      "file": "packages/dashboard/app/components/__tests__/Board.test.tsx",
+      "reason": "FN-6154 local pnpm test run on 2026-06-09 failed in 'Board > multi-lane board (U9, flag ON) > preserves workflow toolbar partial action visibility' with missing .board-workflow-toolbar; unrelated to WorkflowNodeEditor CSS max-height change.",
+      "quarantinedAt": "2026-06-09"
+    }
+  ]
 }