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/packages/markstream-angular/src/utils/languageIcon.ts

@@ -0,0 +1,148 @@
+export type LanguageIconResolver = (lang: string) => string | undefined | null
+
+const DEFAULT_ICON = `
+<svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true">
+  <path d="M14 3h5a2 2 0 0 1 2 2v14a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h5" />
+  <path d="M8 11l-3 3l3 3" />
+  <path d="M16 11l3 3l-3 3" />
+  <path d="M13 9l-2 10" />
+</svg>`
+
+const MERMAID_ICON = `
+<svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true">
+  <rect x="3" y="4" width="7" height="5" rx="1.5" />
+  <rect x="14" y="4" width="7" height="5" rx="1.5" />
+  <rect x="8.5" y="15" width="7" height="5" rx="1.5" />
+  <path d="M10 6.5h4" />
+  <path d="M12 9v2.5" />
+  <path d="M12 11.5l-3.5 3.5" />
+  <path d="M12 11.5l3.5 3.5" />
+</svg>`
+
+const HTML_ICON = `
+<svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true">
+  <path d="M8 7l-4 5l4 5" />
+  <path d="M16 7l4 5l-4 5" />
+  <path d="M14 4l-4 16" />
+</svg>`
+
+const MARKDOWN_ICON = `
+<svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true">
+  <rect x="3" y="4" width="18" height="16" rx="2" />
+  <path d="M7 15V9l3 3l3-3v6" />
+  <path d="M16 9v6" />
+  <path d="M14 13l2 2l2-2" />
+</svg>`
+
+const JSON_ICON = `
+<svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true">
+  <path d="M9 4c-2 0-3 1.5-3 3.5v2c0 1.1-.4 1.8-1.5 2.5C5.6 12.7 6 13.4 6 14.5v2C6 18.5 7 20 9 20" />
+  <path d="M15 4c2 0 3 1.5 3 3.5v2c0 1.1.4 1.8 1.5 2.5c-1.1.7-1.5 1.4-1.5 2.5v2c0 2-1 3.5-3 3.5" />
+</svg>`
+
+const TEXT_ICON = `
+<svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true">
+  <path d="M5 6h14" />
+  <path d="M12 6v12" />
+  <path d="M8 18h8" />
+</svg>`
+
+const LANGUAGE_ALIAS_MAP: Record<string, string> = {
+  '': '',
+  'cjs': 'javascript',
+  'd2lang': 'd2',
+  'js': 'javascript',
+  'jsx': 'jsx',
+  'md': 'markdown',
+  'mjs': 'javascript',
+  'plaintext': 'plain',
+  'py': 'python',
+  'sh': 'shell',
+  'shellscript': 'shell',
+  'text': 'plain',
+  'ts': 'typescript',
+  'tsx': 'tsx',
+}
+
+const LANGUAGE_LABEL_MAP: Record<string, string> = {
+  '': 'Text',
+  'css': 'CSS',
+  'd2': 'D2',
+  'html': 'HTML',
+  'javascript': 'JavaScript',
+  'json': 'JSON',
+  'jsx': 'JSX',
+  'markdown': 'Markdown',
+  'mermaid': 'Mermaid',
+  'plain': 'Text',
+  'plaintext': 'Text',
+  'python': 'Python',
+  'shell': 'Shell',
+  'svg': 'SVG',
+  'tsx': 'TSX',
+  'typescript': 'TypeScript',
+  'vue': 'Vue',
+}
+
+const LANGUAGE_ICON_MAP: Record<string, string> = {
+  '': TEXT_ICON,
+  'html': HTML_ICON,
+  'javascript': DEFAULT_ICON,
+  'json': JSON_ICON,
+  'jsx': DEFAULT_ICON,
+  'markdown': MARKDOWN_ICON,
+  'mermaid': MERMAID_ICON,
+  'plain': TEXT_ICON,
+  'python': DEFAULT_ICON,
+  'shell': DEFAULT_ICON,
+  'svg': HTML_ICON,
+  'tsx': DEFAULT_ICON,
+  'typescript': DEFAULT_ICON,
+}
+
+let userLanguageIconResolver: LanguageIconResolver | null = null
+
+function extractLanguageToken(lang?: string | null) {
+  if (!lang)
+    return ''
+  const trimmed = lang.trim()
+  if (!trimmed)
+    return ''
+  const [firstToken] = trimmed.split(/\s+/)
+  const [base] = firstToken.split(':')
+  return base.toLowerCase()
+}
+
+export function normalizeLanguageIdentifier(lang?: string | null): string {
+  const token = extractLanguageToken(lang)
+  return LANGUAGE_ALIAS_MAP[token] ?? token
+}
+
+export function resolveMonacoLanguageId(lang?: string | null): string {
+  const canonical = normalizeLanguageIdentifier(lang)
+  if (!canonical)
+    return 'plaintext'
+  if (canonical === 'plain')
+    return 'plaintext'
+  if (canonical === 'jsx')
+    return 'javascript'
+  if (canonical === 'tsx')
+    return 'typescript'
+  return canonical
+}
+
+export function setLanguageIconResolver(resolver?: LanguageIconResolver | null) {
+  userLanguageIconResolver = resolver ?? null
+}
+
+export function getLanguageIcon(lang: string): string {
+  if (userLanguageIconResolver) {
+    const hit = userLanguageIconResolver(lang)
+    if (hit != null && hit !== '')
+      return hit
+  }
+  const normalized = normalizeLanguageIdentifier(lang)
+  return LANGUAGE_ICON_MAP[normalized] || DEFAULT_ICON
+}
+
+export const languageMap = LANGUAGE_LABEL_MAP

desktop/libs/markstream-vue/packages/markstream-angular/src/utils/normalizeKaTeXRenderInput.ts

@@ -0,0 +1,8 @@
+export function normalizeKaTeXRenderInput(content: string) {
+  if (!content)
+    return ''
+
+  return content
+    .replace(/·/g, '⋅')
+    .replace(/℃/g, '°C')
+}