fix: address review follow-ups on the canvas stack

[librowski]

Summary

Follow-ups from the second review round on the canvas stack (#124, #126, #136, #139, #140), plus the code side of the design answers from 16.09. The reviewed PRs are approved, so the fixes land here on top of #149.

Review follow-ups (commit 1)

Persist without measured (#124)

• getNodesWithoutDynamicValues also strips the runtime dragging flag; the bundled Demo and AI Studio templates no longer carry dragging: false.
• getStoreDataForIntegration gets two boundary tests; changeset mentions dragging.

Node text ellipsis (#126)

• Docs and changeset state the contain: inline-size constraint (definite inline size on an ancestor; collapses inside inline-flex or fit-content).

Node body spacing (#136)

• Width decision log rewritten with the current derivation and a ## Status section, no external tracker reference; tooltip changeset reworded.

Menu item selected (#139)

• Menu.RadioGroup wrapper gets .group (column flex, --wb-public-list-box-gap), measured 4px between radio items; menu.spec.tsx and node-panel.spec.tsx unmount the React root after each test.

Palette node states (#140)

• The custom node guide and the Demo multi-port template forward disabled to NodePanel.Root, NodeIcon and NodeDescription; node-panel.mdx lists disabled?: boolean; changeset written around WorkflowNodeTemplateProps.disabled with a migration note.

Design answers of 16.09 (commit 2)

• Rows fill the section. In the horizontal layout Decision branches and AI tools take the section width like the design's Node / Row (width: 100%, min-width: 0, no cap); 205px at 241 is the reference value (design draws 209 because a Figma stroke takes no layout space). The derived cap and the Decision min-width: max-content rule now apply to the DOWN layout only, which has no design master. Branch rows and tool rows are spaced with --wb-ds-canvas-node-body-gap (8px; was 4px hard-coded in both places). Decision log updated, the connectable-item-design-width follow-up is closed.
• Self-loop apex at 48px above the node's top edge, independent of node height and port position. SELF_CONNECTING_EDGE_LABEL_OFFSET is 48 and measured from the top edge, as its JSDoc always said; getSelfLoopHeight is exported. Measured in Demo: 48px in the RIGHT layout; 44px in DOWN, where xyflow anchors the bottom port on its outer edge.
• DS Tooltip decided for 3.1: (follow-up: node-text-ds-tooltip) markers on the title attributes in NodeDescription and ConnectableItem.
• Demo multi-port template forwards disabled to NodeIcon and NodeDescription (review remark on commit 1).

Checks

• pnpm -F @workflowbuilder/ui build (includes check:built-css), vitest ui 74 and sdk 219 passing, stylelint ui/sdk clean, typecheck ui/sdk/demo/ai-studio clean.
• Demo measurements (seed with long labels, RIGHT): Decision 241px, rows 205px with truncation, row gap 8px, tool gap 8px, loop apex 48px. DOWN unchanged (525px, capped row 205px).