chore(ci): add baseline test workflow (build + vitest + playwright)

[SyniRon]

Summary

• Adds .github/workflows/ci.yml running on every PR + push to main: pnpm build (which covers tsc -b + vite build + SDE/services generation), pnpm test (vitest), and the Playwright smoke against pnpm preview
• Caches the CCP SDE zip across runs so we're not redownloading ~50MB on every PR
• Patches e2e/playwright.config.ts to fall back to Playwright's bundled Chromium when the synicloud-specific /snap/bin/chromium isn't present

Why now

Surfaced while merging PR #7 — gh pr checks 7 returned "no checks reported" because the repo had no test workflow. The only configured workflow was Dependabot Updates. PRs were merging on local-pnpm test trust. Once this lands, the open Dependabot bumps (#1 Sentry 10, #3 TS 6, #4 plugin-react 5) become safer to merge.

Design notes

• Single job, not split. Build, vitest, and Playwright share the same install + cache; splitting would duplicate the ~50MB SDE pipeline. Revisit if total time exceeds ~5 min.
• pnpm build is the typecheck gate. No separate tsc --noEmit step; the build script's tsc -b covers it.
• SDE cache key is static (freightdesk-sde-zip-v1). scripts/build-sde.ts already self-invalidates the cached zip after 7 days and re-downloads from CCP. A stale cache entry just triggers one extra download.
• Playwright config fix is the minimum viable change. Wrapped the existing snap-Chromium path in existsSync(); macOS dev boxes and Actions runners now silently fall through to Playwright's bundled Chromium. No behavior change on synicloud.

Test plan

• Local: cd web && pnpm test (60/60) — unchanged
• Local: cd e2e && playwright test --list — config parses, 4 tests enumerated
• CI on this PR — first real run will confirm the SDE build, the vitest pass, and the Playwright smoke all work in Actions

🤖 Generated with Claude Code