feat(main): initialize updater, crash writer, and migration on app start

src/main/updater/migration-transform.js

@@ -0,0 +1,55 @@
+// Mirror of src/renderer/lib/migrations/v4-to-v5.ts, plain JS, for main-process use.
+// Kept in sync manually; if the renderer transform changes, update this too.
+const { z } = require('zod');
+
+const v4SettingsSchema = z.object({
+  theme: z.enum(['light', 'dark', 'auto']).default('auto'),
+  customCss: z.string().optional().nullable(),
+  recentFiles: z.array(z.string()).default([]),
+  editorFontSize: z.number().min(10).max(28).default(14),
+  keyBindings: z.record(z.string(), z.string()).optional(),
+  snippets: z.array(z.unknown()).default([]),
+}).passthrough();
+
+const v5SettingsShape = {
+  fontSize: 14,
+  tabSize: 4,
+  lineNumbers: true,
+  wordWrap: true,
+  minimap: true,
+  theme: 'system',
+  accentColor: 'brand',
+  fontFamily: 'system',
+  pdfFormat: 'a4',
+  pdfMargins: 'normal',
+  pdfEmbedFonts: true,
+  docxTemplate: 'standard',
+  docxCustomTemplatePath: null,
+  replOpen: false,
+  breadcrumbSymbols: true,
+  htmlHighlightStyle: 'github',
+  renderTablesAsAscii: false,
+  welcomeDismissed: false,
+  editorFontSize: 14,
+  customCssPath: null,
+  userBindings: {},
+  updateChannel: 'github',
+  autoCheckUpdates: true,
+  firstRun: true,
+};
+
+function migrateV4ToV5(v4) {
+  const parsed = v4SettingsSchema.parse(v4 || {});
+  return {
+    ...v5SettingsShape,
+    ...parsed,
+    theme: parsed.theme === 'auto' ? 'system' : parsed.theme,
+    customCssPath: parsed.customCss ?? null,
+    recentFiles: parsed.recentFiles,
+    editorFontSize: parsed.editorFontSize,
+    userBindings: parsed.keyBindings ?? v5SettingsShape.userBindings,
+    snippets: parsed.snippets,
+  };
+}
+
+module.exports = { migrateV4ToV5, v5SettingsShape };