Test: feature-demos nested-list and clone-mode scenarios skipped

[jjeff]

Problem

Several tests in `tests/e2e/feature-demos.spec.ts` are skipped with TODO comments about hover intercepts, clone-mode integration, and `sort: false` regressions.

Affected tests

• `feature-demos.spec.ts:153` — "can reorder folders using headers as handles" — hover intercepted by parent container.
• `feature-demos.spec.ts:267` — "clones items from source to target list" — HTML5 drag integration issue.
• `feature-demos.spec.ts:313` — "can drag items between lists bidirectionally" — clone-mode follow-up.
• `feature-demos.spec.ts:342` — "source list items cannot be reordered" — `sort: false` not respected (suspect regression).

Suggested approach

These break into two independent concerns:

1. Nested handle hover intercept (one test) — likely a fixture issue in `demo.html`; pointer events landing on the parent container instead of the header.
2. Clone-mode E2E (three tests) — clone semantics (`pull: 'clone'`, `sort: false`) need to be verified end-to-end with the current pointer/HTML5 pipelines.

The `sort: false` failure deserves the closest scrutiny — if this is a real regression we should triage further, otherwise rewrite the test.

Refs #35 — discovered during E2E skip triage.