feat: Implement GraphQL mutations for activities and children

Add complete GraphQL mutation support for activity tracking and child management:

**Activity Mutations:**
- createActivity: Create new activities (feeding, sleep, diaper, medication)
- updateActivity: Update existing activities
- deleteActivity: Delete activities

**Child Mutations:**
- createChild: Add new children to families
- updateChild: Update child information
- deleteChild: Soft delete children

**Implementation Details:**
- Created GraphQL input types (CreateActivityInput, UpdateActivityInput, CreateChildInput, UpdateChildInput)
- Implemented ActivityResolver with full CRUD mutations
- Implemented ChildResolver with full CRUD mutations
- Registered resolvers in GraphQL module with TrackingService and ChildrenService
- Auto-generated GraphQL schema with all mutations
- All mutations protected with GqlAuthGuard for authentication
- Support for JSON metadata fields and Gender enum

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

maternal-web/graphql/queries/dashboard.ts

@@ -0,0 +1,57 @@
+import { gql } from '@apollo/client';
+
+export const GET_DASHBOARD = gql`
+  query GetDashboard($childId: String) {
+    dashboard(childId: $childId) {
+      children {
+        id
+        name
+        birthDate
+        gender
+        photoUrl
+      }
+      selectedChild {
+        id
+        name
+        birthDate
+        gender
+        photoUrl
+      }
+      recentActivities {
+        id
+        type
+        startedAt
+        endedAt
+        notes
+        metadata
+        childId
+        loggedBy
+        logger {
+          id
+          name
+        }
+      }
+      todaySummary {
+        date
+        feedingCount
+        totalFeedingAmount
+        sleepCount
+        totalSleepDuration
+        diaperCount
+        medicationCount
+      }
+      familyMembers {
+        userId
+        familyId
+        role
+        user {
+          id
+          name
+          email
+        }
+      }
+      totalChildren
+      totalActivitiesToday
+    }
+  }
+`;