feat: professional UI redesign + first frontend tests + tutorial video (v1.1.0)

[dimknaf]

Summary

Frontend visual redesign to a Stripe Dashboard-inspired aesthetic, the
first round of frontend test infrastructure (Vitest + RTL, 40 tests
across 5 suites), a tutorial-video embed at the top of the README, and
the first lockstep version bump to v1.1.0.

Changes

Frontend visual (token-based)

• frontend/app/globals.css — full token system (Stripe palette, layered
  duotone shadows, sharp radii), 15px html base, restored typography
  ladder, new utilities (.step-badge, .hero-backdrop, .eyebrow,
  status-dot helpers, .animate-status-pulse).
• frontend/app/page.tsx — full-bleed hero header with Bot brand mark,
  bold wordmark, tagline, and live BackendStatusChip pill (model +
  backend + connection status pulled from /api/agent-status).
• All frontend/components/* swept: dropped 9 bulky padded icon
  containers in favor of inline 16px icons, added numbered step badges
  (1–4) on workflow sections, restored confident heading sizes, denser
  column-tag chips, slimmer progress bar, eyebrow-style form labels.
• KPI stat-card row (Total / Completed / In progress / Failed) above the
  results table.
• FileUpload empty-state polish: 64px gradient icon zone, workflow
  step trail "1 Upload · 2 Configure · 3 Run" underneath.

Bug fix

• FileUpload: full drop-zone is now clickable (was previously only the
  inline "Click to upload" link — the rest of the dashed box did
  nothing despite visually inviting clicks).

Tests

• Vitest 4.1.5 + @testing-library/react 16.3.2 + jsdom 29.1.1 +
  @testing-library/jest-dom 6.9.1 + @testing-library/user-event 14.6.1
  — all pinned to actual latest stable.
• Five suites, 40 tests total: profileUtils (incl. legacy profile
  migration — most load-bearing test per CLAUDE.md), csvParser,
  ColumnTags, OutputSchemaBuilder, ResultsTable.
• .github/workflows/test.yml extended with a frontend job
  (lint + test) running in parallel to backend pytest.

Repo conventions (first-time additions)

• CHANGELOG.md (Keep-a-Changelog)
• CONTRIBUTING.md (Conventional Commits, branch naming, squash-merge,
  lockstep versioning)
• SECURITY.md (private vulnerability reporting)
• .github/PULL_REQUEST_TEMPLATE.md

Documentation

• README.md: tutorial video embed at top
  (youtu.be/wnuQufwRAXE).

Version

• frontend 1.0.0 → 1.1.0 (frontend/package.json)
• backend 1.0.0 → 1.1.0 (backend/API/api.py version literal)
• Lockstep — both sides bump together. Tag: v1.1.0.

Test plan

• cd frontend && npm install && npm run lint && npm run test
  → 40 tests pass, 0 lint warnings
• cd backend && pytest tests/ -v → existing suite still green
• Manual smoke: upload a CSV, click column tags, build prompt,
  define output schema, run with concurrency 2, verify stat cards
  update live, export CSV
• Local Docker stack (docker compose -f docker-compose.local.yml up --build) starts cleanly, frontend at :3000 healthy
• Hero header renders edge-to-edge of viewport on wide screens

Versioning

• Frontend bump (frontend/package.json) — new version: 1.1.0
• Backend bump (backend/API/api.py) — new version: 1.1.0
• CHANGELOG.md updated in this PR

Breaking changes

None. All HTTP API contracts, component props, profile JSON shape, and
runtime behavior are identical to v1.0.0. Pure visual + tooling
refresh.

Checklist

• PR title follows Conventional Commits
• Branch name follows <type>/<short-description>
• Local lint + tests pass for the side(s) I changed