Reorganize worker runtime layer into worker/runtime/ (M8 part 2/3)

Groups the pi Agent lifecycle, factory, signature contract, and env/redaction helpers into src/main/worker/runtime/. WorkerRunner is the module's public entry and lives in runtime/index.ts; pi-agent-factory and pi-hook-contract stay named for their role as visible runtime boundaries; helpers.ts carries ParentMessage/ChildMessage/RunJob types plus redactor + env override utilities. entry/index.ts and agent-runtime/runtime-message-injector.ts updated to import from the new paths.

src/main/worker/entry/index.ts

@@ -1,6 +1,6 @@
-import type { ChildMessage, ParentMessage, RunJob } from "../worker-helpers";
+import type { ChildMessage, ParentMessage, RunJob } from "../runtime/helpers";
 import { WorkerRpcClient } from "./rpc";
-import { WorkerRunner } from "../worker-runner";
+import { WorkerRunner } from "../runtime";
 
 const parentPort = process.parentPort;
 

src/main/worker/entry/rpc.ts

@@ -1,5 +1,5 @@
 import { randomUUID } from "node:crypto";
-import type { ChildMessage } from "../worker-helpers";
+import type { ChildMessage } from "../runtime/helpers";
 
 interface PendingRpc {
   resolve: (value: { ok: true; result: unknown } | { ok: false; error: string }) => void;

src/main/worker/runtime/index.ts

@@ -1,11 +1,11 @@
 import type { Agent, AgentMessage } from "@mariozechner/pi-agent-core";
-import { resolveModel, resolveExtraStreamHeaders } from "../model-resolver";
+import { resolveModel, resolveExtraStreamHeaders } from "../../model-resolver";
 import type { RunStatus } from "@shared/types";
-import type { ChildMessage, RunJob } from "./worker-helpers";
-import { applyEnvOverrides, buildRedactor } from "./worker-helpers";
+import type { ChildMessage, RunJob } from "./helpers";
+import { applyEnvOverrides, buildRedactor } from "./helpers";
 import { createCodingTools } from "@mariozechner/pi-coding-agent";
 import { createPiAgent, resolveThinkingLevel } from "./pi-agent-factory";
-import type { WorkerRpcClient } from "./entry/rpc";
+import type { WorkerRpcClient } from "../entry/rpc";
 
 interface PrepareRunResult {
   provider: string;

src/main/worker/runtime/pi-agent-factory.ts

@@ -29,7 +29,7 @@ import type {
   TransformContextRpcPayload,
   TransformContextRpcResult,
 } from "@main/agent-runtime/hook-rpc";
-import type { WorkerRpcClient } from "./entry/rpc";
+import type { WorkerRpcClient } from "../entry/rpc";
 // Side-effect import: drags the hook signature contract into the typecheck
 // graph so any drift in pi-agent-core hook shapes breaks the build here.
 import "./pi-hook-contract";