move pi-mono into companion-cloud as apps/companion-os

- Copy all pi-mono source into apps/companion-os/
- Update Dockerfile to COPY pre-built binary instead of downloading from GitHub Releases
- Update deploy-staging.yml to build pi from source (bun compile) before Docker build
- Add apps/companion-os/** to path triggers
- No more cross-repo dispatch needed

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/ai/test/google-thinking-signature.test.ts

@@ -0,0 +1,56 @@
+import { describe, expect, it } from "vitest";
+import {
+  isThinkingPart,
+  retainThoughtSignature,
+} from "../src/providers/google-shared.js";
+
+describe("Google thinking detection (thoughtSignature)", () => {
+  it("treats part.thought === true as thinking", () => {
+    expect(isThinkingPart({ thought: true, thoughtSignature: undefined })).toBe(
+      true,
+    );
+    expect(
+      isThinkingPart({ thought: true, thoughtSignature: "opaque-signature" }),
+    ).toBe(true);
+  });
+
+  it("does not treat thoughtSignature alone as thinking", () => {
+    // Per Google docs, thoughtSignature is for context replay and can appear on any part type.
+    // Only thought === true indicates thinking content.
+    // See: https://ai.google.dev/gemini-api/docs/thought-signatures
+    expect(
+      isThinkingPart({
+        thought: undefined,
+        thoughtSignature: "opaque-signature",
+      }),
+    ).toBe(false);
+    expect(
+      isThinkingPart({ thought: false, thoughtSignature: "opaque-signature" }),
+    ).toBe(false);
+  });
+
+  it("does not treat empty/missing signatures as thinking if thought is not set", () => {
+    expect(
+      isThinkingPart({ thought: undefined, thoughtSignature: undefined }),
+    ).toBe(false);
+    expect(isThinkingPart({ thought: false, thoughtSignature: "" })).toBe(
+      false,
+    );
+  });
+
+  it("preserves the existing signature when subsequent deltas omit thoughtSignature", () => {
+    const first = retainThoughtSignature(undefined, "sig-1");
+    expect(first).toBe("sig-1");
+
+    const second = retainThoughtSignature(first, undefined);
+    expect(second).toBe("sig-1");
+
+    const third = retainThoughtSignature(second, "");
+    expect(third).toBe("sig-1");
+  });
+
+  it("updates the signature when a new non-empty signature arrives", () => {
+    const updated = retainThoughtSignature("sig-1", "sig-2");
+    expect(updated).toBe("sig-2");
+  });
+});