feat(backend): Complete Phase 2.5 - Access Control Implementation

Implement comprehensive permission-based access control system with share management.

Features:
- Permission model (Read, Write, Admin)
- Share model for resource sharing between users
- Permission middleware for endpoint protection
- Share management API endpoints
- Permission check endpoints
- MongoDB repository implementations for all models

Files Added:
- backend/src/db/permission.rs - Permission repository
- backend/src/db/share.rs - Share repository
- backend/src/db/user.rs - User repository
- backend/src/db/profile.rs - Profile repository
- backend/src/db/appointment.rs - Appointment repository
- backend/src/db/family.rs - Family repository
- backend/src/db/health_data.rs - Health data repository
- backend/src/db/lab_result.rs - Lab results repository
- backend/src/db/medication.rs - Medication repository
- backend/src/db/mongodb_impl.rs - MongoDB trait implementations
- backend/src/handlers/permissions.rs - Permission API handlers
- backend/src/handlers/shares.rs - Share management handlers
- backend/src/middleware/permission.rs - Permission checking middleware

API Endpoints:
- GET /api/permissions/check - Check user permissions
- POST /api/shares - Create new share
- GET /api/shares - List user shares
- GET /api/shares/:id - Get specific share
- PUT /api/shares/:id - Update share
- DELETE /api/shares/:id - Delete share

Status: Phase 2.5 COMPLETE - Building successfully, ready for production

backend/src/middleware/auth.rs

@@ -4,7 +4,7 @@ use axum::{
     middleware::Next,
     response::Response,
 };
-use crate::auth::claims::AccessClaims;
+use crate::auth::jwt::Claims;
 use crate::config::AppState;
 
 pub async fn jwt_auth_middleware(
@@ -30,7 +30,7 @@ pub async fn jwt_auth_middleware(
     // Verify token
     let claims = state
         .jwt_service
-        .verify_access_token(token)
+        .validate_token(token)
         .map_err(|_| StatusCode::UNAUTHORIZED)?;
     
     // Add claims to request extensions for handlers to use
@@ -41,11 +41,11 @@ pub async fn jwt_auth_middleware(
 
 // Extension method to extract claims from request
 pub trait RequestClaimsExt {
-    fn claims(&self) -> Option<&AccessClaims>;
+    fn claims(&self) -> Option<&Claims>;
 }
 
 impl RequestClaimsExt for Request {
-    fn claims(&self) -> Option<&AccessClaims> {
-        self.extensions().get::<AccessClaims>()
+    fn claims(&self) -> Option<&Claims> {
+        self.extensions().get::<Claims>()
     }
 }