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>

backend/app/api/router.py

@@ -1,6 +1,7 @@
 from fastapi import APIRouter
 from app.api.endpoints import auth, trees, sessions, invite, categories, tags, folders, step_categories, steps, admin, accounts, webhooks, shares, shared, tree_markdown
 from app.api.endpoints import admin_dashboard, admin_audit, admin_plan_limits, admin_feature_flags, admin_settings, admin_categories
+from app.api.endpoints import ratings, analytics
 
 api_router = APIRouter()
 
@@ -25,3 +26,5 @@ api_router.include_router(webhooks.router)
 api_router.include_router(shares.router)
 api_router.include_router(shared.router)  # Public endpoints (no auth)
 api_router.include_router(tree_markdown.router)
+api_router.include_router(ratings.router)
+api_router.include_router(analytics.router)