fix(e2e): platform-aware chromium resolver + pin playwright CLI (Phase 0.3)

`tests/e2e/lib_helpers.cjs` and `tests/e2e/test_task8_modularization.mjs`
both hard-coded `process.env.LOCALAPPDATA + "/ms-playwright/chromium-1208/
chrome-win64/chrome.exe"`. On a Linux CI runner LOCALAPPDATA is undefined,
so chromium.launch() was asked to start `"undefined/ms-playwright/.../chrome.exe"`
— Windows binary path on Linux, double bug. Latest e2e-smoke.yml run
(25877702139) failed at the first smoke step with exactly this error.

Replaced the hard-coded constant with a `resolveChromiumExecutable()`
helper:
  1. honor `PLAYWRIGHT_CHROMIUM_EXECUTABLE_PATH` env override
  2. on Windows with LOCALAPPDATA set, preserve the legacy path so local
     dev keeps working
  3. otherwise return `undefined` and let `playwright-core` auto-resolve
     from the standard `~/.cache/ms-playwright/` location

Launch site only sets `executablePath` when the resolver returns a value,
so playwright-core can use its bundled discovery on Linux CI.

Second bug surfaced while reading the workflow log: `npx playwright
install` was unpinned and pulled the latest playwright (1.60.0 in the
failed run) — but package.json pins `playwright-core@1.59.1`. The CLI
would have installed chromium at a revision playwright-core wouldn't
look for at runtime. Pinned all three browser-install workflow steps
(`e2e-smoke.yml`, `e2e-full.yml`, `a11y-audit.yml`) to
`npx playwright@1.59.1 install --with-deps chromium` so the installed
chromium revision matches what playwright-core resolves.

Verification:
- Local Windows: `node -e` of the resolver returns the existing
  `C:\Users\PC\AppData\Local\ms-playwright\chromium-1208\chrome-win64\
  chrome.exe` path — local dev behavior unchanged.
- Linux CI: resolver returns `undefined`, launch options omit
  `executablePath`, playwright-core discovers chromium installed by
  `npx playwright@1.59.1 install`.
- Workflow green on next push will be the ground-truth signal; this
  commit is being pushed specifically to exercise it.

Per Phase 0.3 of `docs/PUBLIC_RELEASE_PLAN.md` ("Fix e2e-smoke.yml
Playwright `undefined` env var failure — Windows binary path appears
on Linux runner").

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: wildleo91

.github/workflows/a11y-audit.yml

@@ -52,7 +52,11 @@ jobs:
         run: npm ci
 
       - name: Install Playwright browsers
-        run: npx playwright install --with-deps chromium
+        # Pin to the same minor as playwright-core in package.json
+        # (currently 1.59.1) so the installed chromium revision matches
+        # what playwright-core resolves at runtime. See e2e-smoke.yml
+        # for the full explanation.
+        run: npx playwright@1.59.1 install --with-deps chromium
 
       - name: Start Splunk container
         run: docker compose up -d

.github/workflows/e2e-full.yml

@@ -62,7 +62,11 @@ jobs:
         run: npm ci
 
       - name: Install Playwright browsers
-        run: npx playwright install --with-deps chromium
+        # Pin to the same minor as playwright-core in package.json
+        # (currently 1.59.1) so the installed chromium revision matches
+        # what playwright-core resolves at runtime. See e2e-smoke.yml
+        # for the full explanation.
+        run: npx playwright@1.59.1 install --with-deps chromium
 
       - name: Start Splunk container
         run: docker compose up -d

.github/workflows/e2e-smoke.yml

@@ -64,7 +64,12 @@ jobs:
         # — we need an explicit install. Chromium is the only browser
         # tests/e2e/ uses (per lib_helpers.cjs), so we install just it
         # to keep CI runner provisioning fast.
-        run: npx playwright install --with-deps chromium
+        #
+        # MUST pin to the same minor as playwright-core in package.json
+        # (currently 1.59.1). Without a pin, `npx playwright install`
+        # downloads the latest `playwright` CLI which installs a chromium
+        # revision that playwright-core@1.59.x won't find at runtime.
+        run: npx playwright@1.59.1 install --with-deps chromium
 
       - name: Start Splunk container
         run: docker compose up -d

tests/e2e/lib_helpers.cjs

@@ -1,8 +1,20 @@
 /**
  * Shared helpers for multi-role E2E tests.
  */
+const path = require("node:path");
 const { chromium } = require("playwright-core");
-const CHROME = process.env.LOCALAPPDATA + "/ms-playwright/chromium-1208/chrome-win64/chrome.exe";
+
+function resolveChromiumExecutable() {
+    if (process.env.PLAYWRIGHT_CHROMIUM_EXECUTABLE_PATH) {
+        return process.env.PLAYWRIGHT_CHROMIUM_EXECUTABLE_PATH;
+    }
+    if (process.platform === "win32" && process.env.LOCALAPPDATA) {
+        return path.join(process.env.LOCALAPPDATA, "ms-playwright", "chromium-1208", "chrome-win64", "chrome.exe");
+    }
+    return undefined;
+}
+
+const CHROME = resolveChromiumExecutable();
 const BASE = "http://localhost:8000";
 const REST = "https://localhost:8089";
 
@@ -40,7 +52,9 @@ function summary(label) {
 }
 
 async function createSession(user, pass) {
-    const browser = await chromium.launch({ headless: true, executablePath: CHROME });
+    const launchOpts = { headless: true };
+    if (CHROME) launchOpts.executablePath = CHROME;
+    const browser = await chromium.launch(launchOpts);
     const context = await browser.newContext({ ignoreHTTPSErrors: true, viewport: { width: 1440, height: 900 } });
     const page = await context.newPage();
     page.__errors = [];

tests/e2e/test_task8_modularization.mjs

@@ -16,8 +16,19 @@
  *   9. Edge cases: concurrent actions, unusual characters, empty state
  */
 
+import path from "node:path";
 import { chromium } from "playwright-core";
 
+function resolveChromiumExecutable() {
+    if (process.env.PLAYWRIGHT_CHROMIUM_EXECUTABLE_PATH) {
+        return process.env.PLAYWRIGHT_CHROMIUM_EXECUTABLE_PATH;
+    }
+    if (process.platform === "win32" && process.env.LOCALAPPDATA) {
+        return path.join(process.env.LOCALAPPDATA, "ms-playwright", "chromium-1208", "chrome-win64", "chrome.exe");
+    }
+    return undefined;
+}
+
 const BASE = "http://localhost:8000";
 const LOGIN_URL = `${BASE}/en-US/account/login`;
 const WM_URL = `${BASE}/en-US/app/wl_manager/whitelist_manager`;
@@ -94,8 +105,10 @@ async function getConsoleErrors() {
 // Main test runner
 // ══════════════════════════════════════════════════════════════════
 async function run() {
-    const chromePath = process.env.LOCALAPPDATA + "/ms-playwright/chromium-1208/chrome-win64/chrome.exe";
-    browser = await chromium.launch({ headless: true, executablePath: chromePath });
+    const chromePath = resolveChromiumExecutable();
+    const launchOpts = { headless: true };
+    if (chromePath) launchOpts.executablePath = chromePath;
+    browser = await chromium.launch(launchOpts);
     context = await browser.newContext({
         ignoreHTTPSErrors: true,
         viewport: { width: 1440, height: 900 }