feat: upgrade to upstream v2026.3.28

Major upgrade from e26988a38 to upstream v2026.3.28 (f9b107928).
Key changes:
- Upstream src/, ui/, extensions/ (89 bundled extensions)
- Zero-token web providers preserved in src/zero-token/
- AskOnce plugin restored and registered as CLI command
- Added missing packages: @anthropic-ai/vertex-sdk, @modelcontextprotocol/sdk
- Fixed tsconfig rootDir, skipLibCheck for plugin-sdk DTS build
- Added askonce to bundled plugin metadata and package.json exports
- Fixed AskOnce CLI command registration (missing commands metadata)
- Restored AskOnce adapter imports (correct 5-level relative paths)
- Removed stale migration artifacts from root directory

extensions/github-copilot/usage.ts

@@ -0,0 +1,69 @@
+import {
+  buildUsageHttpErrorSnapshot,
+  fetchJson,
+  clampPercent,
+  PROVIDER_LABELS,
+  type ProviderUsageSnapshot,
+  type UsageWindow,
+} from "openclaw/plugin-sdk/provider-usage";
+
+type CopilotUsageResponse = {
+  quota_snapshots?: {
+    premium_interactions?: { percent_remaining?: number | null };
+    chat?: { percent_remaining?: number | null };
+  };
+  copilot_plan?: string;
+};
+
+export async function fetchCopilotUsage(
+  token: string,
+  timeoutMs: number,
+  fetchFn: typeof fetch,
+): Promise<ProviderUsageSnapshot> {
+  const res = await fetchJson(
+    "https://api.github.com/copilot_internal/user",
+    {
+      headers: {
+        Authorization: `token ${token}`,
+        "Editor-Version": "vscode/1.96.2",
+        "User-Agent": "GitHubCopilotChat/0.26.7",
+        "X-Github-Api-Version": "2025-04-01",
+      },
+    },
+    timeoutMs,
+    fetchFn,
+  );
+
+  if (!res.ok) {
+    return buildUsageHttpErrorSnapshot({
+      provider: "github-copilot",
+      status: res.status,
+    });
+  }
+
+  const data = (await res.json()) as CopilotUsageResponse;
+  const windows: UsageWindow[] = [];
+
+  if (data.quota_snapshots?.premium_interactions) {
+    const remaining = data.quota_snapshots.premium_interactions.percent_remaining;
+    windows.push({
+      label: "Premium",
+      usedPercent: clampPercent(100 - (remaining ?? 0)),
+    });
+  }
+
+  if (data.quota_snapshots?.chat) {
+    const remaining = data.quota_snapshots.chat.percent_remaining;
+    windows.push({
+      label: "Chat",
+      usedPercent: clampPercent(100 - (remaining ?? 0)),
+    });
+  }
+
+  return {
+    provider: "github-copilot",
+    displayName: PROVIDER_LABELS["github-copilot"],
+    windows,
+    plan: data.copilot_plan,
+  };
+}