feat(ui): redesign public reading and complete glass workspace

Add scoped public navigation, reading progress, focus and print controls without loading the editor. Polish responsive settings, graph and media layouts.

Correct share expiry units, preserve math and code during link maintenance, and normalize Markdown destinations for templates and note navigation. Verify browser flows and document the new tools.

web/src/clipboard.ts

@@ -0,0 +1,19 @@
+// 写入剪贴板；Clipboard API 只在 HTTPS/localhost 可用，局域网 HTTP 访问时退回 execCommand
+export async function copyText(text: string): Promise<boolean> {
+  if (navigator.clipboard && window.isSecureContext) {
+    try {
+      await navigator.clipboard.writeText(text)
+      return true
+    } catch {
+      // 权限被拒时继续尝试旧方法
+    }
+  }
+  const ta = document.createElement('textarea')
+  ta.value = text
+  ta.style.cssText = 'position:fixed;top:0;left:0;opacity:0'
+  document.body.append(ta)
+  ta.select()
+  const ok = document.execCommand('copy')
+  ta.remove()
+  return ok
+}