Intent: preserve nested lists inside list items

[noeltock]

Problem

Nested lists vanished inside intent list items while reporting success. Closes #126.

Solution

Pass assembled children into native list-item construction.

Behaviour	Read first	Proof
Preserve nested hierarchy, ordered attributes and siblings	src/intent/index.ts	Two-level parsed-tree regressions
Keep plain list shorthand	dev/test/intent.test.ts	Existing and added intent tests

Diff

+39 / −1 across two files.

 assembleNode
- paragraph and list-item -> createBlock(name, attrs, [])
+ paragraph -> createBlock(name, attrs, [])
+ list-item -> createBlock(name, attrs, children)

Testing & verification

Reviewed revision: 765e49f91b6f10e1f6d40d9d330a26ae0f6bcb3a · Environment: Node 24.18.0, macOS arm64.

• npx vitest run dev/test/intent.test.ts: 14 passed. Both nested cases failed on the prior implementation (3 blocks instead of 8).
• npm run typecheck: passed.
• npm run verify: passed (727 tests, four existing skips; build, dependency support, authoring hashes, private-reference and package checks). Full PR CI passed: https://github.com/humanmade/block-runner/actions/runs/37173800280 (Node 20/22/24, packed consumers, WordPress proof and scope gate).
• CLI issue reproduction: four valid blocks, zero warnings.

Not verified: target-site rendering and manual editor acceptance. The regression proves preservation through the pinned headless parse/serialize gate.

Risk / rollout

List items now retain their intended children; the shared finalization gate remains unchanged. No configuration or migration.

Detection: parsed-tree regression failures. Rollback: revert this PR.