fix: update E2E flow tests to match current UI selectors

[Sealjay]

Summary

Three E2E test suites are skipped because their selectors don't match the current UI after the shadcn/ui migration:

• frontend/e2e/character-creation.spec.ts
• frontend/e2e/complete-e2e-workflow.spec.ts
• frontend/e2e/user-journey.spec.ts

Problem

These tests use plain CSS class selectors (.campaign-setup, .character-card) and button text matching (button:has-text("Create Campaign")) that no longer exist in the rendered DOM. The shadcn migration introduced CSS modules (hashed class names) and changed button labels.

Fix needed

1. Add data-testid attributes to key interactive elements across campaign, character, and game components
2. Update test selectors to use data-testid instead of fragile class/text matching
3. Remove test.describe.skip / test.skip() once tests pass
4. Re-enable nightly schedule in .github/workflows/e2e-tests.yml once green

Skipped in

Commit 9eeede4 — test: skip broken E2E flow tests until selectors are fixed