fix: install Playwright browsers in sjer.red CI container

The Playwright Docker base image provides system dependencies but not
the browser binaries matching the app's Playwright version. Add explicit
browser installation with cache volume, matching birmel's pattern.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: claude

.dagger/src/sjer-red.ts

@@ -1,9 +1,11 @@
 import type { Directory, Container, Secret } from "@dagger.io/dagger";
 import { dag } from "@dagger.io/dagger";
 import { syncToS3 } from "./lib-s3.ts";
-import versions from "./lib-versions.ts";
+import versions, { type Versions } from "./lib-versions.ts";
 import { getBuiltEslintConfig } from "./lib-eslint-config.ts";
 
+const PLAYWRIGHT_VERSION: Versions["playwright"] = versions.playwright;
+
 function getBunContainer(): Container {
   return dag
     .container()
@@ -24,7 +26,12 @@ function getPlaywrightContainer(): Container {
       "-c",
       `curl -fsSL https://bun.sh/install | bash -s "bun-v${versions.bun}"`,
     ])
-    .withEnvVariable("PATH", "/root/.bun/bin:$PATH", { expand: true });
+    .withEnvVariable("PATH", "/root/.bun/bin:$PATH", { expand: true })
+    .withMountedCache(
+      "/root/.cache/ms-playwright",
+      dag.cacheVolume(`playwright-browsers-sjerred-${PLAYWRIGHT_VERSION}`),
+    )
+    .withExec(["bunx", "playwright", "install", "--with-deps", "chromium"]);
 }
 
 /**