refactor(desktop): extract project-dir + workspace settings IPC from main.cjs into project-dir-ipc.cjs

Sixth main.cjs cluster peel. The hermes:setting:defaultProjectDir:get/set/pick
handlers + hermes:workspace:sanitize move verbatim into
electron/project-dir-ipc.cjs behind a registerProjectDirIpc({ ipcMain,
readDefaultProjectDir, writeDefaultProjectDir, resolveHermesCwd,
sanitizeWorkspaceCwd }) registrar. The config readers/writers + cwd resolvers stay
in the main process and are injected.

Channel names unchanged → preload + renderer untouched. Adds
electron/project-dir-ipc.test.cjs (surface + set/sanitize behavior; get/pick touch
Electron app/dialog and are exercised in-app only).

apps/desktop/electron/main.cjs

@@ -61,6 +61,7 @@ const { registerFsIpc } = require('./fs-ipc.cjs')
 const { registerTerminalIpc } = require('./terminal-ipc.cjs')
 const { registerUpdatesIpc } = require('./updates-ipc.cjs')
 const { registerLogsIpc } = require('./logs-ipc.cjs')
+const { registerProjectDirIpc } = require('./project-dir-ipc.cjs')
 const { OFFICIAL_REPO_HTTPS_URL, isOfficialSshRemote } = require('./update-remote.cjs')
 const { resolveBehindCount, shouldCountCommits } = require('./update-count.cjs')
 const { runRebuildWithRetry } = require('./update-rebuild.cjs')
@@ -6663,42 +6664,14 @@ ipcMain.handle('hermes:openPreviewInBrowser', async (_event, url) => {
 // settings mount and seeds the value into the picker; writing back persists
 // it via writeDefaultProjectDir so resolveHermesCwd picks it up on the next
 // session spawn (no app restart needed).
-ipcMain.handle('hermes:setting:defaultProjectDir:get', async () => ({
-  dir: readDefaultProjectDir(),
-  defaultLabel: app.getPath('home'),
-  resolvedCwd: resolveHermesCwd()
-}))
-
-ipcMain.handle('hermes:workspace:sanitize', async (_event, cwd) => sanitizeWorkspaceCwd(cwd))
-
-ipcMain.handle('hermes:setting:defaultProjectDir:set', async (_event, dir) => {
-  const next = typeof dir === 'string' && dir.trim() ? dir.trim() : null
-
-  if (next) {
-    try {
-      fs.mkdirSync(next, { recursive: true })
-    } catch (error) {
-      throw new Error(`Could not create directory: ${error.message}`)
-    }
-  }
-
-  writeDefaultProjectDir(next)
-
-  return { dir: next }
-})
-
-ipcMain.handle('hermes:setting:defaultProjectDir:pick', async () => {
-  const result = await dialog.showOpenDialog({
-    title: 'Choose default project directory',
-    properties: ['openDirectory', 'createDirectory'],
-    defaultPath: readDefaultProjectDir() || app.getPath('home')
-  })
-
-  if (result.canceled || result.filePaths.length === 0) {
-    return { canceled: true, dir: null }
-  }
-
-  return { canceled: false, dir: result.filePaths[0] }
+// Default-project-dir + workspace settings IPC lives in project-dir-ipc.cjs;
+// config readers/writers + cwd resolvers are injected.
+registerProjectDirIpc({
+  ipcMain,
+  readDefaultProjectDir,
+  resolveHermesCwd,
+  sanitizeWorkspaceCwd,
+  writeDefaultProjectDir
 })
 
 ipcMain.handle('hermes:fetchLinkTitle', (_event, url) => fetchLinkTitle(url))

apps/desktop/electron/project-dir-ipc.cjs

@@ -0,0 +1,55 @@
+'use strict'
+
+const { app, dialog } = require('electron')
+const fs = require('fs')
+
+// Default-project-directory + workspace-cwd settings IPC: read / write / native
+// directory picker, plus workspace-cwd sanitize. The config readers/writers and
+// cwd resolvers live in the main process and are injected.
+function registerProjectDirIpc({
+  ipcMain,
+  readDefaultProjectDir,
+  resolveHermesCwd,
+  sanitizeWorkspaceCwd,
+  writeDefaultProjectDir
+}) {
+  ipcMain.handle('hermes:setting:defaultProjectDir:get', async () => ({
+    dir: readDefaultProjectDir(),
+    defaultLabel: app.getPath('home'),
+    resolvedCwd: resolveHermesCwd()
+  }))
+
+  ipcMain.handle('hermes:workspace:sanitize', async (_event, cwd) => sanitizeWorkspaceCwd(cwd))
+
+  ipcMain.handle('hermes:setting:defaultProjectDir:set', async (_event, dir) => {
+    const next = typeof dir === 'string' && dir.trim() ? dir.trim() : null
+
+    if (next) {
+      try {
+        fs.mkdirSync(next, { recursive: true })
+      } catch (error) {
+        throw new Error(`Could not create directory: ${error.message}`)
+      }
+    }
+
+    writeDefaultProjectDir(next)
+
+    return { dir: next }
+  })
+
+  ipcMain.handle('hermes:setting:defaultProjectDir:pick', async () => {
+    const result = await dialog.showOpenDialog({
+      title: 'Choose default project directory',
+      properties: ['openDirectory', 'createDirectory'],
+      defaultPath: readDefaultProjectDir() || app.getPath('home')
+    })
+
+    if (result.canceled || result.filePaths.length === 0) {
+      return { canceled: true, dir: null }
+    }
+
+    return { canceled: false, dir: result.filePaths[0] }
+  })
+}
+
+module.exports = { registerProjectDirIpc }

apps/desktop/electron/project-dir-ipc.test.cjs

@@ -0,0 +1,63 @@
+'use strict'
+
+const assert = require('node:assert/strict')
+const test = require('node:test')
+
+const { registerProjectDirIpc } = require('./project-dir-ipc.cjs')
+
+function fakeIpcMain() {
+  const handlers = new Map()
+
+  return {
+    handlers,
+    handle(channel, handler) {
+      assert.ok(!handlers.has(channel), `duplicate registration for ${channel}`)
+      handlers.set(channel, handler)
+    }
+  }
+}
+
+function deps(overrides = {}) {
+  return {
+    readDefaultProjectDir: () => '/projects',
+    resolveHermesCwd: () => '/cwd',
+    sanitizeWorkspaceCwd: cwd => `safe:${cwd}`,
+    writeDefaultProjectDir: () => {},
+    ...overrides
+  }
+}
+
+test('registerProjectDirIpc wires the project-dir + workspace settings channels', () => {
+  const ipcMain = fakeIpcMain()
+
+  registerProjectDirIpc({ ipcMain, ...deps() })
+
+  assert.deepEqual([...ipcMain.handlers.keys()].sort(), [
+    'hermes:setting:defaultProjectDir:get',
+    'hermes:setting:defaultProjectDir:pick',
+    'hermes:setting:defaultProjectDir:set',
+    'hermes:workspace:sanitize'
+  ])
+})
+
+// `get` / `pick` touch Electron's `app` / `dialog`, which are unavailable under
+// `node --test` (require('electron') is a path stub), so they're exercised in-app
+// only. The wiring of all four channels is covered by the surface test above.
+
+test('set normalizes a blank dir to null and persists that (clears the override)', async () => {
+  const ipcMain = fakeIpcMain()
+  const writes = []
+
+  registerProjectDirIpc({ ipcMain, ...deps({ writeDefaultProjectDir: d => writes.push(d) }) })
+
+  assert.deepEqual(await ipcMain.handlers.get('hermes:setting:defaultProjectDir:set')({}, '   '), { dir: null })
+  assert.deepEqual(writes, [null])
+})
+
+test('workspace:sanitize delegates to the injected sanitizer', async () => {
+  const ipcMain = fakeIpcMain()
+
+  registerProjectDirIpc({ ipcMain, ...deps() })
+
+  assert.equal(await ipcMain.handlers.get('hermes:workspace:sanitize')({}, '/x'), 'safe:/x')
+})