fix(web): disable indented code blocks in markdown rendering

[hqhq1025]

Problem

LLM responses with indented content (e.g. numbered list items with nested text, quoted documents) render as large code blocks instead of formatted markdown.

Root cause

CommonMark treats text indented by 4+ spaces as a code block (codeIndented). LLM output frequently contains:

• Numbered list items with nested paragraphs
• Quoted/referenced text with extra indentation
• Task descriptions indented for readability

The markdown parser correctly follows the spec, but the result is unusable — entire sections become unformatted code blocks.

Fix

Add a remark plugin that disables the codeIndented tokenizer in micromark. Fenced code blocks (```) continue to work normally. This is a common practice for chat/LLM UIs where indentation is decorative, not semantic.

Changes

• web/src/lib/remark-disable-indented-code.ts — new remark plugin
• web/src/components/assistant-ui/markdown-text.tsx — add plugin to MARKDOWN_PLUGINS

Test plan

• All 104 existing tests pass
• Verify: LLM responses with indented lists render as formatted markdown, not code blocks
• Verify: fenced code blocks (```) still render correctly

[github-actions]

Findings

• [Major] The new remark plugin relies on an implicit-any this, which conflicts with the repo's strict TypeScript config and should fail typechecking once dependencies are installed. Evidence web/src/lib/remark-disable-indented-code.ts:11, repo config tsconfig.base.json:7.
  Suggested fix:

  type RemarkData = {
      micromarkExtensions?: Array<{ disable: { null: string[] } }>
  }
  
  export default function remarkDisableIndentedCode(this: { data(): RemarkData }) {
      const data = this.data()
      const extensions = data.micromarkExtensions ?? (data.micromarkExtensions = [])
      extensions.push({ disable: { null: ['codeIndented'] } })
  }

Summary
Review mode: initial
1 major finding on the latest diff. I could not run bun-based checks in this automation environment, but this issue follows directly from the repo's strict TypeScript settings and the added plugin implementation.

Testing

• Not run (automation environment does not have bun)
• Residual gap: no markdown rendering regression test found for indented text vs fenced code

HAPI Bot

[github-actions]

[MAJOR] const self = this as any still uses an implicit-any this before the cast, so this should trip the repo's strict TypeScript settings (tsconfig.base.json:7).

Suggested fix:

type RemarkData = {
    micromarkExtensions?: Array<{ disable: { null: string[] } }>
}

export default function remarkDisableIndentedCode(this: { data(): RemarkData }) {
    const data = this.data()
    const extensions = data.micromarkExtensions ?? (data.micromarkExtensions = [])
    extensions.push({ disable: { null: ['codeIndented'] } })
}

[github-actions]

Findings

• None on the added/modified lines in the latest head.

Summary
Review mode: follow-up after new commits
No actionable issues found in the latest diff. Residual risk: I did not find a web regression test covering indented list/quoted text rendering versus fenced code rendering, so future markdown/parser changes could regress this behavior without detection.

Testing

• Not run (automation)
• Not found in repo/docs: a web markdown rendering regression test for indented text versus fenced code

HAPI Bot