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-seq-open-error-probe.spec.ts

@@ -0,0 +1,20 @@
+import fs from "node:fs";
+import path from "node:path";
+import { test } from "@playwright/test";
+import { observeNative } from "../fixtures/native-ui-workflow";
+
+const root = path.resolve(import.meta.dirname, "../../..");
+
+test("capture open failure for sequence.blend", async ({ page }) => {
+  test.setTimeout(180_000);
+  await observeNative(page);
+  await page.goto("/");
+  await page.getByTestId("blend-file-input").setInputFiles(path.join(root, "blender-5.2.0/tests/files/sequence_editing/sequence.blend"));
+  await page.waitForTimeout(25000);
+  const out = await page.evaluate(() => ({
+    status: document.querySelector('[data-testid="engine-status"]')?.textContent ?? "",
+    title: document.querySelector('[data-testid="engine-status"]')?.getAttribute("title") ?? "",
+    responses: ((window as any).__nativeWorkflowResponses ?? []).slice(-4).map((r: any) => ({ ok: r.ok, code: r.error?.code, message: String(r.error?.message ?? "").slice(0, 400) })),
+  }));
+  fs.writeFileSync("/tmp/seq-open-error.json", JSON.stringify(out, null, 2));
+});