feat: build Intervention Tracking and Best Practices workflow with reassessment and worksheet linking

[Ashishpatra0-0]

What this PR does

The problem: The backend already had a fully-built Intervention Tracking and Best
Practices system (routes, database models, seed data, and automatic outcome detection)
but there was zero frontend integration. A misleading placeholder in the Teacher
Dashboard ("Use sidebar → Interventions") pointed to a sidebar link that didn't exist.

What I built:

Core Feature (frontend integration on top of existing backend)

• Fixed the orphaned sidebar link and misleading dashboard placeholder
• Built the full Intervention Tracking page: view interventions, create new plans,
  see auto-detected outcomes (improved/not improved with level before→after)
• Built the Best Practices Repository page: search, filter by strategy, sort by
  level jump, browse proven strategies from other teachers
• Added a "Promote to Best Practice" button connecting interventions to the
  repository
• Added an editable Teacher Notes field for ongoing collaborative observations
• Integrated an "Intervention Plan" tab into the Student Profile page

New backend features

1. Reassessment Trigger - activates the previously-unused pending_review
   status. Calculates whether an intervention's planned duration has elapsed
   and allows the teacher to trigger a follow-up assessment once due, with a
   live countdown shown on each card.
2. Worksheet Matching Engine - a new endpoint that scores and ranks existing
   worksheets by how well their questions match an intervention's weak
   competencies (not just a static list - real relevance scoring based on
   question topic/subtopic overlap).
3. Worksheet Linking - teachers can link recommended worksheets to
   an intervention plan, with a persistent display and a modal to view full
   worksheet contents (including reconstructing full question text where the
   seed data had been truncated).
4. Linked worksheets now carry through to promoted Best Practice entries.

Files changed

Backend:

• backend/src/db.ts — added linkedWorksheetIds to Intervention and BestPractice
• backend/src/index.ts — added /trigger-reassessment, /suggested-worksheets,
  /linked-worksheets, /notes, and /worksheets/:id/view routes

Frontend:

• frontend/src/components/Layout.tsx — added Interventions + Best Practices
  navigation entries
• frontend/src/components/RoleDashboards.tsx — fixed the orphaned placeholder
  banner to link to the real Interventions page
• frontend/src/components/InterventionTracking.tsx — new component (main feature)
• frontend/src/components/BestPractices.tsx — new component
• frontend/src/components/PanelViews.tsx — added Intervention Plan tab to
  Student Profile

How I tested this

• Verified via direct API calls (curl/PowerShell) that each new backend route
  works correctly before wiring up the frontend
• Created test interventions, linked worksheets, verified match scoring against
  real worksheet data
• Tested the reassessment countdown/trigger by adjusting test data timestamps
• Confirmed role-based permissions (only owning teacher or admins can edit
  notes/worksheets)
• Tested across Teacher and Superadmin accounts to confirm scoping works correctly