feat: analytics dashboards & two-tier feedback system (#78)

* docs: add analytics & user feedback design document

Covers team analytics, personal analytics, flow analytics,
step-level thumbs up/down feedback, and flow CSAT ratings.

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

* docs: add analytics & feedback implementation plan

12-task TDD plan covering session ratings, step feedback,
team/personal/flow analytics endpoints, and frontend pages.

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

* feat: add session_ratings table and analytics indexes

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

* feat: add SessionRating model and analytics schemas

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

* feat: add session CSAT rating endpoint with tests

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

* feat: add step thumbs feedback and /ratings alias routes

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

* feat: add team, personal, and flow analytics endpoints

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

* feat: add recharts, analytics types, and API client

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

* feat: add inline step thumbs up/down feedback during sessions

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

* feat: add CSAT rating modal after session completion

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

* feat: add Team Analytics page with charts and leaderboards

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

* feat: add Flow Analytics panel with step dropoff and CSAT data

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

* feat: add My Analytics page with personal stats and charts

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

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

frontend/package.json

@@ -32,6 +32,7 @@
     "react-dom": "^19.2.0",
     "react-markdown": "^10.1.0",
     "react-router-dom": "^7.13.0",
+    "recharts": "^3.7.0",
     "sonner": "^2.0.7",
     "tailwind-merge": "^3.4.0",
     "zundo": "^2.3.0",