chore: drop non-code junk (pi-mono-reference, runtime state, root duplicates)

Remove files that should never have been tracked:

- pi-mono-reference/: 688-file copy of an upstream monorepo, zero imports,
  used only as offline human reference
- build/electron-builder.runtime.json: environment-specific build artifact
  with hardcoded local paths
- state/cancel-signal-state.json: runtime state written by the app
- prompt.txt, logo.svg (root): exact duplicates of the canonical copies
  under .planning/archive/ and assets/

Add state/ to .gitignore so future runtime state stays out.

pi-mono-reference/packages/ai/test/google-tool-call-missing-args.test.ts

@@ -1,105 +0,0 @@
-import { Type } from "@sinclair/typebox";
-import { afterEach, describe, expect, it, vi } from "vitest";
-import { streamGoogleGeminiCli } from "../src/providers/google-gemini-cli.js";
-import type { Context, Model, ToolCall } from "../src/types.js";
-
-const emptySchema = Type.Object({});
-
-const originalFetch = global.fetch;
-
-afterEach(() => {
-	global.fetch = originalFetch;
-	vi.restoreAllMocks();
-});
-
-describe("google providers tool call missing args", () => {
-	it("defaults arguments to empty object when provider omits args field", async () => {
-		// Simulate a tool call response where args is missing (no-arg tool)
-		const sse = `${[
-			`data: ${JSON.stringify({
-				response: {
-					candidates: [
-						{
-							content: {
-								role: "model",
-								parts: [
-									{
-										functionCall: {
-											name: "get_status",
-											// args intentionally omitted
-										},
-									},
-								],
-							},
-							finishReason: "STOP",
-						},
-					],
-					usageMetadata: {
-						promptTokenCount: 10,
-						candidatesTokenCount: 5,
-						totalTokenCount: 15,
-					},
-				},
-			})}`,
-		].join("\n\n")}\n\n`;
-
-		const encoder = new TextEncoder();
-		const dataStream = new ReadableStream<Uint8Array>({
-			start(controller) {
-				controller.enqueue(encoder.encode(sse));
-				controller.close();
-			},
-		});
-
-		const fetchMock = vi.fn(async () => {
-			return new Response(dataStream, {
-				status: 200,
-				headers: { "content-type": "text/event-stream" },
-			});
-		});
-
-		global.fetch = fetchMock as typeof fetch;
-
-		const model: Model<"google-gemini-cli"> = {
-			id: "gemini-2.5-flash",
-			name: "Gemini 2.5 Flash",
-			api: "google-gemini-cli",
-			provider: "google-gemini-cli",
-			baseUrl: "https://cloudcode-pa.googleapis.com",
-			reasoning: false,
-			input: ["text"],
-			cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
-			contextWindow: 128000,
-			maxTokens: 8192,
-		};
-
-		const context: Context = {
-			messages: [{ role: "user", content: "Check status", timestamp: Date.now() }],
-			tools: [
-				{
-					name: "get_status",
-					description: "Get current status",
-					parameters: emptySchema,
-				},
-			],
-		};
-
-		const stream = streamGoogleGeminiCli(model, context, {
-			apiKey: JSON.stringify({ token: "token", projectId: "project" }),
-		});
-
-		for await (const _ of stream) {
-			// consume stream
-		}
-
-		const result = await stream.result();
-
-		expect(result.stopReason).toBe("toolUse");
-		expect(result.content).toHaveLength(1);
-
-		const toolCall = result.content[0] as ToolCall;
-		expect(toolCall.type).toBe("toolCall");
-		expect(toolCall.name).toBe("get_status");
-		expect(toolCall.arguments).toEqual({});
-	});
-});