[aicayzer]

Restyles code blocks, the Terminal block and the fold rule to the approved design. No page prose changes.

What changes for a reader

• A code block is a white card with a hairline border and rounded corners.
• Every block has one header row: a bold label (the block's title, or "Terminal") or, for code tabs, soft pill tabs, with a Copy button at the right. A block with no title and no tabs gets a header row with Copy only.
• A Terminal shows one body: the command, then its output in muted text. Copy takes the command only. The separate "Output" fold is gone.
• One fold rule: any block or terminal body over 24 lines shows its first lines with a fade and a "Show all N lines" button under a hairline.
• Request and response blocks can add a lighter note (note="Server-sent events") or a status chip (status="200", drawn "200 OK"; green for 2xx, red for 4xx and 5xx) in the header.
• A response body is highlighted in normal colour. A new sse language colours an event stream's field names and its data: JSON.
• The generated API reference's request samples and response status tabs use the same look.

Fence syntax

```http title="Request"
```http title="Response" note="Server-sent events"
```json title="Response" status="200"

The Markdown copy prints the note or status above the block, such as "Response (Server-sent events):" and "Response (200 OK):".

Checked

• Built-in browser, light and dark: Terminal, request and response blocks with note and status, code tabs, a 43-line fold open and closed, the API reference operation page (request samples and response status tabs).
• Phone width (375px): no horizontal page scroll on /guides/keep-in-sync and /quickstart.
• Markdown copy of /guides/keep-in-sync.md.
• pnpm build, pnpm build:status, pnpm types:check, pnpm test (700 tests) pass.

Not checked

• Existing pages do not use note, status or sse yet; the checks above used temporary edits to the guide that are not in this pull request.
• Before and after screenshots for August's approval are not attached here.

STYLE.md is updated for the Terminal, fold, title, note and status rules and the Markdown copy.

[aicayzer]

Review: checks only

Styling change, looked at in the browser by the builder and again by the session; build, type check and tests pass.