feat: Merge dataset label application with new label creation

[cephalization]

apply.and.create.labels.mov

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Note

Integrates dataset label creation directly into the dataset label assignment popover and removes ComboBox portal/container props across the app, adding a shared label-mutations hook.

• Dataset Labels:
  • Integrated Create + Apply Flow: DatasetLabelConfigButton now toggles between applying existing labels and creating new ones within the same popover (apply/create modes), removing separate modals.
  • New Hook: Adds useDatasetLabelMutations to centralize label creation, error handling, and Relay connection updates; updates NewDatasetLabelDialog to use it.
  • UI tweaks: Fixed popover widths, list height constraints, back button, and conditional search; minor submenu popover sizing in DatasetActionMenu.
• ComboBox:
  • Removes container/portal usage; Popover renders without UNSTABLE_portalContainer. Sets default width to "100%".
  • Cleans up all consumers to drop container prop (ModelComboBox, ModelConfigButton fields, PromptComboBox, SavePromptForm).
• GraphQL/Relay:
  • Adds generated mutation useDatasetLabelMutationsAddLabelMutation and uses @prependNode to update DatasetLabelEdge connections.

^{Written by Cursor Bugbot for commit 17c8597. This will update automatically on new commits. Configure here.}

[cephalization]

this breaks modals that have dropdowns/popovers inside of them, like the playground model settings dialog

[axiomofjoy]

Do we still need the fragment?

[cephalization]

No