chore: checkpoint web Blender migration source, tools and docs

Accumulated uncommitted work: GHOST Web backend, WebGL/GPU web layer,
web workflow engine and protocol, tooling, docs and task records.
Large generated evidence, user-testing archives, build snapshots and
imported test assets remain untracked.

Co-Authored-By: Claude Code <noreply@anthropic.com>

web/tests/e2e/b3-reset-filepath-probe.spec.ts

@@ -0,0 +1,38 @@
+import fs from "node:fs";
+import path from "node:path";
+import { test, expect } from "@playwright/test";
+import { NativeUIWorkflow, observeNative } from "../fixtures/native-ui-workflow";
+
+const root = path.resolve(import.meta.dirname, "../../..");
+const fixture = path.join(root, "tests/files/web/basic_scene.blend");
+
+test("probe filepath survival across pythonReset", async ({ page }, testInfo) => {
+  test.setTimeout(180_000);
+  await observeNative(page);
+  await page.goto("/");
+  const flow = new NativeUIWorkflow(page, testInfo.outputPath("cases"));
+  await flow.command(() => page.getByTestId("blend-file-input").setInputFiles(fixture));
+  await expect(page.getByTestId("engine-status")).toContainText("SceneIR", { timeout: 60000 });
+  const out = await page.evaluate(async () => {
+    const worker = (window as any).__nativeWorkflowEngine as Worker;
+    const send = (command: any) => new Promise<any>((resolve, reject) => {
+      const requestId = `rp-${crypto.randomUUID()}`;
+      const receive = (event: MessageEvent) => {
+        if (event.data?.requestId !== requestId || event.data?.kind !== 'result') return;
+        worker.removeEventListener('message', receive);
+        if (event.data.ok) resolve(event.data.result); else reject(new Error(`${event.data.error?.code}: ${event.data.error?.message}`));
+      };
+      worker.addEventListener('message', receive); worker.postMessage({ requestId, command });
+    });
+    const py = (source: string) => send({ type: 'jsonCommand', cmd: 'pythonExec', params: { source, filename: 'Rp.py', console: false } });
+    const log: any = {};
+    log.before = String((await py("import bpy\nprint(repr(bpy.data.filepath))")).json?.output ?? '').trim();
+    try {
+      await send({ type: 'jsonCommand', cmd: 'pythonReset', params: {} });
+      log.reset = 'ok';
+    } catch (e: any) { log.reset = String(e?.message ?? e); }
+    log.after = String((await py("import bpy\nprint(repr(bpy.data.filepath))")).json?.output ?? '').trim();
+    return log;
+  });
+  fs.writeFileSync("/tmp/reset-filepath.json", JSON.stringify(out, null, 2));
+});