refactor(desktop): establish TypeScript base across desktop

.agents/session-log.md

@@ -389,7 +389,8 @@
 - 2026-04-10: Completed issue #342 primary workbench ownership. The renderer now marks workbench-heavy surfaces explicitly and collapses the outer support lane plus internal two-column workbench grids earlier, so `Runs`, `Compare`, `Candidates`, `Run Detail`, and `Paper Ops` stop holding two side rails at the same laptop-width breakpoint. Validation passed with `node --check desktop/renderer/app.js`, `npm run smoke:fallback`, and `npm run smoke:real-path`.
 - 2026-04-10: Started issue #346 to harden `desktop-smoke` result persistence after CI repeatedly failed with raw `ENOENT` on missing `result.json` in a planning-only PR. The slice is limited to `desktop/main.js`, `desktop/scripts/smoke.js`, and `.agents` continuity so smoke emits structured failures instead of crashing when Electron exits too early.
 - 2026-04-10: Added the desktop layout regression remediation block after reviewing the post-merge desktop state in real screenshots. Opened issues #342, #343, and #344 to target empty-pane collapse, stronger active-surface focus and context containment, and better runs-family density plus right-rail space budgeting without reopening core or `research_ui` scope.
-<<<<<<< HEAD
 - 2026-04-10: Added the Desktop architecture migration block after accepting the ADR direction for the new shell foundation. Opened issues #350, #354, #353, #355, #352, #359, #351, #357, #358, and #356 so the migration is tracked as real slices rather than dozens of micro-backlog items.
 - 2026-04-10: Started the desktop shared contracts foundation slice on branch `codex/desktop-shared-workspace-contract`. The goal is to establish the first real shared Desktop contract layer before opening the larger `desktop-typescript-base` slice, limited to workspace, runtime/snapshot, and smoke boundaries.
 - 2026-04-10: Completed the desktop shared contracts foundation slice. Added `desktop/shared` contracts for IPC channels, envelopes, workspace state, runtime state, snapshot status, and smoke results, and connected them back into `desktop/main.js`, `desktop/preload.js`, `desktop/renderer/app.js`, and `desktop/scripts/smoke.js` via narrow JSDoc typing only, without changing desktop behavior.
+- 2026-04-10: Started issue #354 on branch `codex/desktop-typescript-base`. This slice is limited to the real TypeScript base for `desktop/`: `tsconfig.json`, `types/global.d.ts`, package wiring, and only the minimum edits required in `main.js`, `preload.js`, and `renderer/app.js` so typecheck passes without changing desktop behavior.
+- 2026-04-10: Completed issue #354 TypeScript base real across Desktop. Added `desktop/tsconfig.json`, `desktop/types/global.d.ts`, and package wiring for `typecheck`, then applied only the minimum `@ts-check` and DOM/type narrowing changes in `desktop/main.js`, `desktop/preload.js`, and `desktop/renderer/app.js` so `npm run typecheck`, `node --check`, `npm run smoke:fallback`, and `npm run smoke:real-path` all pass without changing visible desktop behavior.

.agents/tasks/issue-354-typescript-base-across-desktop.md

@@ -1,15 +1,60 @@
 # Issue #354 — TypeScript Base Across Desktop
 
 ## Goal
-Establish the real TypeScript base for `desktop/` without changing runtime behavior.
+Establish the real TypeScript base for `desktop/` without changing runtime behavior or opening the renderer migration yet.
+
+---
+
+## Why this matters
+- turns `desktop/shared` into a first-class typed contract layer
+- prepares the modularization of `main.js` without spreading JS debt into more files first
+- keeps the migration sequence disciplined: contracts first, tooling second, architecture refactor third
+
+---
+
+## Scope
+
+### In scope
+- `desktop/tsconfig.json`
+- `desktop/types/global.d.ts`
+- `desktop/package.json`
+- minimal typecheck-driven edits in `desktop/main.js`, `desktop/preload.js`, and `desktop/renderer/app.js`
+- native consumption of `desktop/shared/ipc` and `desktop/shared/models`
+
+### Out of scope
+- modularizing `main.js`
+- React
+- Vite
+- `research_ui`
+- new shared models
+- functional behavior changes
+- visible UI changes
+
+---
+
+## Relevant files
+
+- `desktop/package.json`
+- `desktop/tsconfig.json`
+- `desktop/types/global.d.ts`
+- `desktop/main.js`
+- `desktop/preload.js`
+- `desktop/renderer/app.js`
+- `desktop/shared/`
+
+---
 
 ## Expected deliverable
-- `tsconfig.json`
-- `types/global.d.ts`
-- `typecheck`
-- native use of `desktop/shared`
+
+- TypeScript base configuration for the current Desktop shell
+- current Desktop entrypoints passing `typecheck` while staying in JS
+- no runtime behavior change
+
+---
 
 ## Done when
-- current Desktop JS entrypoints pass typecheck
-- smoke remains green
-- no functional change is introduced
+
+- `npm run typecheck` passes in `desktop/`
+- `node --check` passes for touched JS entrypoints
+- `smoke:fallback` and `smoke:real-path` stay green
+- `main.js`, `preload.js`, and `renderer/app.js` consume `desktop/shared` natively through the TS base

desktop/main.js

@@ -1,3 +1,5 @@
+// @ts-check
+
 const { app, BrowserWindow, ipcMain, shell } = require("electron");
 const fs = require("fs");
 const fsp = require("fs/promises");

desktop/package.json

@@ -7,14 +7,17 @@
   "scripts": {
     "start": "electron .",
     "dev": "electron .",
+    "typecheck": "tsc --project tsconfig.json --noEmit",
     "smoke": "npm run smoke:fallback",
     "smoke:fallback": "node scripts/smoke.js --mode=fallback",
     "smoke:real-path": "node scripts/smoke.js --mode=real-path",
     "mcp": "node mcp-server.mjs"
   },
   "devDependencies": {
     "@modelcontextprotocol/sdk": "^1.20.0",
+    "@types/node": "^24.6.1",
     "electron": "^37.2.0",
+    "typescript": "^5.9.3",
     "zod": "^4.1.12"
   }
 }

desktop/preload.js

@@ -1,3 +1,5 @@
+// @ts-check
+
 const { contextBridge, ipcRenderer } = require("electron");
 
 /** @typedef {import("./shared/models/workspace").WorkspaceState} WorkspaceState */