Fix blank drawings, drop parse-time animation cost, add render diagnostics

Accuracy / completeness
- docViews: split parsed scene into model space / paper space / free-standing
  blocks (geometry hidden in uninserted blocks no longer shows as a blank
  canvas); auto-select the first block view when model space is empty
- viewer: view switcher panel listing every detected view with expanded
  entity counts; paper space is now parsed (includePaperSpace) and kept apart
- SHX: missing .shx references are surfaced with an import control
  (addReferenceFile), linetypes/text redraw afterwards
- unsupported/proxy entities: markers on canvas + diagnostics block showing
  proxy / wipeout counts and missing SHX names

Speed
- the loading overlay used an infinite CSS spinner + backdrop blur while the
  worker parsed; on software rendering that starved the parse thread
  (TELECOM 18MB: 71s -> 30s wall clock, normalize 33s -> 14s). Replaced with a
  determinate progress bar fed by loader progress events
- transferInputBuffer for worker loads, maxInsertDepth 32, longer worker timeout

Tooling
- scripts/probe-dwg.mjs / probe-app.mjs: headless render + end-to-end probes
  (entity/layer/block/layout/proxy stats, timings, screenshots)
- tools/render-probe.html, scripts/profile-worker.mjs
- version 0.6.0 (versionCode 8)

tools/worker-node-run.mjs

@@ -0,0 +1,49 @@
+// 在 Node 里直接跑 DWG worker 的解析流程（带 CPU profile），用于定位热点。
+// 用法：node --cpu-prof --cpu-prof-dir=/tmp/prof tools/worker-node-run.mjs <dwg> <静态资源根 URL>
+import fs from 'node:fs'
+import path from 'node:path'
+import { pathToFileURL } from 'node:url'
+
+const root = process.cwd()
+const file = process.argv[2]
+const wasmBase = process.argv[3] || 'http://127.0.0.1:8123/wasm/'
+if (!file) throw new Error('需要 DWG 路径')
+
+const messages = []
+globalThis.self = {
+  postMessage(msg) {
+    messages.push(msg)
+    if (msg.type === 'result') {
+      const doc = msg.result?.document
+      console.log('结果: 实体', doc?.entities?.length, '耗时', Math.round(msg.result.elapsedMs), 'ms')
+      for (const m of messages.filter((x) => x.type === 'progress')) {
+        console.log('  progress', m.progress.phase, '|', m.progress.message)
+      }
+      process.exit(0)
+    }
+    if (msg.type === 'error') {
+      console.error('worker 错误:', msg.error)
+      process.exit(1)
+    }
+  },
+  addEventListener() {},
+  removeEventListener() {}
+}
+globalThis.performance = performance
+globalThis.window = globalThis // 让 Emscripten 走 Web 分支（用 fetch 而不是 node:module）
+
+await import(pathToFileURL(path.join(root, 'public/wasm/dwg-worker.js')).href)
+
+const bytes = fs.readFileSync(file)
+const buf = bytes.buffer.slice(bytes.byteOffset, bytes.byteOffset + bytes.byteLength)
+const started = Date.now()
+await globalThis.self.onmessage({
+  data: {
+    requestId: 1,
+    type: 'load',
+    bytes: buf,
+    fileName: path.basename(file),
+    options: { wasmPath: wasmBase }
+  }
+})
+console.log('总耗时', Date.now() - started, 'ms')