test(desktop): Playwright electron e2e harness

Launches the built app (out/main/index.js) via Playwright's _electron
API — no browser project, no chromium download. Adds a launch fixture
(electronApp/window/app), an AppPage page object with a screenshot
helper for autonomous visual review, and a boot smoke suite (shell
renders, @commitea/core label-parse runs in the renderer, preload API
exposed). Scripts: e2e (build+run), e2e:only, e2e:report. Artifacts
gitignored.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

yarn.lock

@@ -241,6 +241,7 @@ __metadata:
   resolution: "@commitea/desktop@workspace:apps/desktop"
   dependencies:
     "@commitea/core": "workspace:*"
+    "@playwright/test": "npm:^1.61.1"
     "@types/node": "npm:^22.13.1"
     "@types/react": "npm:^18.3.18"
     "@types/react-dom": "npm:^18.3.5"
@@ -720,6 +721,17 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@playwright/test@npm:^1.61.1":
+  version: 1.61.1
+  resolution: "@playwright/test@npm:1.61.1"
+  dependencies:
+    playwright: "npm:1.61.1"
+  bin:
+    playwright: cli.js
+  checksum: 10c0/45004139eaa7c7ec8129e4ed77a9d734aa09ed40b69162b871e4123f1d70217b7b73651431a9343ed5090d5fed11c6df1bff2a56ff4b87dc7b0371b5da87cf9c
+  languageName: node
+  linkType: hard
+
 "@rolldown/pluginutils@npm:1.0.0-beta.27":
   version: 1.0.0-beta.27
   resolution: "@rolldown/pluginutils@npm:1.0.0-beta.27"
@@ -1890,6 +1902,16 @@ __metadata:
   languageName: node
   linkType: hard
 
+"fsevents@npm:2.3.2":
+  version: 2.3.2
+  resolution: "fsevents@npm:2.3.2"
+  dependencies:
+    node-gyp: "npm:latest"
+  checksum: 10c0/be78a3efa3e181cda3cf7a4637cb527bcebb0bd0ea0440105a3bb45b86f9245b307dc10a2507e8f4498a7d4ec349d1910f4d73e4d4495b16103106e07eee735b
+  conditions: os=darwin
+  languageName: node
+  linkType: hard
+
 "fsevents@npm:~2.3.2, fsevents@npm:~2.3.3":
   version: 2.3.3
   resolution: "fsevents@npm:2.3.3"
@@ -1900,6 +1922,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"fsevents@patch:fsevents@npm%3A2.3.2#optional!builtin<compat/fsevents>":
+  version: 2.3.2
+  resolution: "fsevents@patch:fsevents@npm%3A2.3.2#optional!builtin<compat/fsevents>::version=2.3.2&hash=df0bf1"
+  dependencies:
+    node-gyp: "npm:latest"
+  conditions: os=darwin
+  languageName: node
+  linkType: hard
+
 "fsevents@patch:fsevents@npm%3A~2.3.2#optional!builtin<compat/fsevents>, fsevents@patch:fsevents@npm%3A~2.3.3#optional!builtin<compat/fsevents>":
   version: 2.3.3
   resolution: "fsevents@patch:fsevents@npm%3A2.3.3#optional!builtin<compat/fsevents>::version=2.3.3&hash=df0bf1"
@@ -2458,6 +2489,30 @@ __metadata:
   languageName: node
   linkType: hard
 
+"playwright-core@npm:1.61.1":
+  version: 1.61.1
+  resolution: "playwright-core@npm:1.61.1"
+  bin:
+    playwright-core: cli.js
+  checksum: 10c0/c28896ba82a602182e240ed4f9c467fb0dd9cb57d510f8aba9f25183fe1cde3a0105725a29baffa4157fe885bbb11e228032a2aad0424111584fde45303f07bd
+  languageName: node
+  linkType: hard
+
+"playwright@npm:1.61.1":
+  version: 1.61.1
+  resolution: "playwright@npm:1.61.1"
+  dependencies:
+    fsevents: "npm:2.3.2"
+    playwright-core: "npm:1.61.1"
+  dependenciesMeta:
+    fsevents:
+      optional: true
+  bin:
+    playwright: cli.js
+  checksum: 10c0/cea1bc4d2a64ec3ef683891606774029da7b8a8036ed98332565cec2f8e89549ca1fab9a89fbfba4e08e27e0d7e7d148031e965af66d5ff97bb3c34058cfcad0
+  languageName: node
+  linkType: hard
+
 "postcss-import@npm:^15.1.0":
   version: 15.1.0
   resolution: "postcss-import@npm:15.1.0"