[P2] Add E2E regression test for project selection and data entry

[kgarg2468]

Problem

No automated regression guard exists for the reported broken path: select project -> open Data tab -> enter/save inputs.

Scope

• Add Playwright E2E test for project selection and data input/save flow.
• Cover success path and one load-failure path.

Acceptance Criteria

• CI/local E2E fails if project click no longer opens editable Data form.
• Test verifies at least one field can be entered and persisted.

Suggested Files

• Playwright test directory (create if missing)
• app/(app)/data/page.tsx (stable selectors/hooks)