fix(electron): keep the backend specs on the base compile target

The ES2022 target moves from apps/electron-backend/tsconfig.json to
tsconfig.app.json, so it applies to the main-process and preload build
only. Compiling the Jest specs for ES2022 dropped the downleveled helpers
from Istanbul's statement counts (downloads.events.ts: 126 -> 111
statements, 79 -> 71 covered, 62.69% -> 63.96%) and tripped the absolute
minimumCovered ratchet in tools/coverage/coverage-policy.json without any
coverage being lost. The shipped bundles are byte-identical either way.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/electron-backend/tsconfig.app.json

@@ -3,7 +3,9 @@
     "compilerOptions": {
         "outDir": "../../dist/out-tsc",
         "types": ["node"],
-        "importHelpers": false
+        "importHelpers": false,
+        "target": "ES2022",
+        "useDefineForClassFields": false
     },
     "files": ["../../global.d.ts"],
     "exclude": [

apps/electron-backend/tsconfig.json

@@ -4,9 +4,7 @@
         "types": ["node"],
         "moduleResolution": "nodenext",
         "module": "NodeNext",
-        "ignoreDeprecations": "6.0",
-        "target": "ES2022",
-        "useDefineForClassFields": false
+        "ignoreDeprecations": "6.0"
     },
     "include": ["**/*.ts"]
 }

docs/development/electron-debugging.md

@@ -135,10 +135,15 @@ from `app.asar`. The preload is
 [DB worker](../architecture/sqlite-db-worker.md) for worker ownership and
 [Electron security](../architecture/electron-security.md) for bridge boundaries.
 
-`apps/electron-backend/tsconfig.json` sets `"target": "ES2022"` for the
-main-process bundles (`main.js`, `main.app.js`, `deferred-events.js`), the
-preloads and the backend's Jest specs; `tsconfig.base.json` stays at `es2015`
-because other projects inherit it. Electron 43 (Node 24 and Chromium's V8) runs
+`apps/electron-backend/tsconfig.app.json` sets `"target": "ES2022"` for the
+main-process bundles (`main.js`, `main.app.js`, `deferred-events.js`) and the
+preloads; `tsconfig.base.json` stays at `es2015` because other projects
+inherit it. The Jest specs (`tsconfig.spec.json`) keep the base target on
+purpose: Istanbul counts the statements of the emitted code, so an ES2022 spec
+build drops the downleveled helpers from the counts (for example
+`downloads.events.ts` from 126 to 111 statements) and would trip the absolute
+`minimumCovered` ratchets in `tools/coverage/coverage-policy.json` without any
+coverage being lost. Electron 43 (Node 24 and Chromium's V8) runs
 ES2022 natively in the main process and in the sandboxed preload, so
 async/await, optional chaining and `??` are no longer downleveled.
 `"useDefineForClassFields": false` keeps the class-field semantics of the old