Blockquote Autoformat Port 3000

Goal

Reproduce and fix the reported blockquote autoformat regression where typing > does not promote to a blockquote on localhost:3000.

Context

• User explicitly asked for live repro on port 3000.
• Need fresh browser verification, not code-only guessing.
• Existing learnings already mention a prior nested blockquote autoformat bug.

Relevant Learnings

• docs/solutions/ui-bugs/2026-04-02-blockquote-autoformat-must-wrap-nested-quotes.md
• docs/solutions/best-practices/block-fence-input-rules-should-split-fence-matching-from-feature-apply.md
• docs/solutions/best-practices/input-rules-should-register-explicit-rule-instances-while-packages-export-markdown-families.md

Working Plan

• Load relevant skills
• Reproduce the bug on localhost:3000
• Identify the owner lane and current missing coverage
• Add failing regression test
• Fix the root cause
• Verify in browser and targeted checks

Findings

• Core already had package-level unit coverage in packages/basic-nodes/src/lib/BaseBlockquoteInputRules.spec.tsx.
• What was missing was app-level shipped-kit coverage. Added apps/www/src/__tests__/package-integration/blockquote/basic-blocks-kit.slow.tsx to lock both root and nested > promotion in BasicBlocksKit.
• The real bug was deeper than blockquote. createRuleFactory built object-config rules without feeding config defaults into runtime resolver input. That made callbacks like ({ marker }) => marker resolve to undefined in realistic editor flows.
• Fixed packages/core/src/lib/plugins/input-rules/createRuleFactory.ts to merge object-config defaults into the runtime factory input.
• Added core regression coverage in packages/core/src/lib/plugins/input-rules/createRuleFactory.spec.ts.
• Browser automation on /blocks/basic-blocks-demo was noisy for raw keystroke typing, but pulling the live editor instance from the page and applying the real editor transforms on localhost:3000 proved the fixed path now produces a trailing blockquote after insertBreak() + > + text.