feat(desktop): embed BoosAPI Desktop client as a subproject

Vendor the rebranded BoosAPI Desktop client (Tauri + Vue) into metapi as
a monorepo subdirectory under desktop/. Source only — node_modules,
dist, Cargo target and the upstream .git history are excluded.

desktop/ keeps its own independent Cargo workspace (desktop/src-tauri
with crates/*); it is not part of the backend boosapi crate, so a
`cargo check` at the metapi root still compiles only the backend. Build
the desktop app from desktop/src-tauri per desktop/README.md.

Note: app icons are still placeholder assets pending the final BoosAPI
logo. The updater signing keys live outside the repo and are not
included.

desktop/libs/markstream-vue/test/blockquote-regressions.test.ts

@@ -0,0 +1,28 @@
+import { getMarkdown, parseMarkdownToStructure } from 'stream-markdown-parser'
+import { describe, expect, it } from 'vitest'
+
+describe('blockquote regressions', () => {
+  const md = getMarkdown('blockquote-regressions')
+
+  it('keeps tables nested inside blockquotes', () => {
+    const markdown = `> PCB描述如下：
+>
+> | 料号 | 品名 | 规格 |
+> | -- | -- | -- |
+> | 120300-5420-01 | PCB | 临时物料-枪机项目-型号：507AA＿SENSOR＿V10-单板尺寸：27.33＊39.22＊1.0mm-4层-FR4-黑油-拼板-4＊4-拼版尺寸：129.32＊162.88＊1.0mm-0SP-TG＞＝150℃ MOT＞＝130℃-环保测试（RoHS2.0）-五株 [1]`
+
+    const nodes = parseMarkdownToStructure(markdown, md)
+    expect(nodes.length).toBe(1)
+    const blockquote: any = nodes[0]
+    expect(blockquote.type).toBe('blockquote')
+
+    const hasParagraph = blockquote.children?.some((child: any) => child.type === 'paragraph')
+    expect(hasParagraph).toBe(true)
+
+    const tableNode: any = blockquote.children?.find((child: any) => child.type === 'table')
+    expect(tableNode).toBeTruthy()
+    expect(tableNode.rows?.[0]?.cells?.length).toBe(3)
+    const firstCellText = tableNode.rows?.[0]?.cells?.[0]?.children?.[0]?.content || ''
+    expect(firstCellText).toContain('120300-5420-01')
+  })
+})