style: apply rustfmt to backend codebase

- Apply rustfmt to all Rust source files in backend/
- Fix trailing whitespace inconsistencies
- Standardize formatting across handlers, models, and services
- Improve code readability with consistent formatting

These changes are purely stylistic and do not affect functionality.
All CI checks now pass with proper formatting.

backend/src/models/medication.rs

@@ -1,8 +1,8 @@
-use serde::{Deserialize, Serialize};
-use mongodb::bson::{oid::ObjectId, DateTime, doc};
-use mongodb::Collection;
-use futures::stream::StreamExt;
 use super::health_data::EncryptedField;
+use futures::stream::StreamExt;
+use mongodb::bson::{doc, oid::ObjectId, DateTime};
+use mongodb::Collection;
+use serde::{Deserialize, Serialize};
 
 // ============================================================================
 // PILL IDENTIFICATION (Phase 2.8)
@@ -14,11 +14,11 @@ pub struct PillIdentification {
     /// Size of the pill (optional)
     #[serde(skip_serializing_if = "Option::is_none")]
     pub size: Option<PillSize>,
-    
+
     /// Shape of the pill (optional)
     #[serde(skip_serializing_if = "Option::is_none")]
     pub shape: Option<PillShape>,
-    
+
     /// Color of the pill (optional)
     #[serde(skip_serializing_if = "Option::is_none")]
     pub color: Option<PillColor>,
@@ -27,11 +27,11 @@ pub struct PillIdentification {
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(rename_all = "lowercase")]
 pub enum PillSize {
-    Tiny,      // < 5mm
-    Small,     // 5-10mm
-    Medium,    // 10-15mm
-    Large,     // 15-20mm
-    ExtraLarge,// > 20mm
+    Tiny,       // < 5mm
+    Small,      // 5-10mm
+    Medium,     // 10-15mm
+    Large,      // 15-20mm
+    ExtraLarge, // > 20mm
     #[serde(rename = "custom")]
     Custom(String),
 }
@@ -114,7 +114,7 @@ pub struct Medication {
     pub created_at: DateTime,
     #[serde(rename = "updatedAt")]
     pub updated_at: DateTime,
-    
+
     /// Physical pill identification (Phase 2.8 - optional)
     #[serde(skip_serializing_if = "Option::is_none")]
     pub pill_identification: Option<PillIdentification>,
@@ -167,7 +167,7 @@ pub struct CreateMedicationRequest {
     pub tags: Option<Vec<String>>,
     pub reminder_times: Option<Vec<String>>,
     pub profile_id: String,
-    
+
     /// Pill identification (Phase 2.8 - optional)
     #[serde(rename = "pill_identification")]
     pub pill_identification: Option<PillIdentification>,
@@ -189,7 +189,7 @@ pub struct UpdateMedicationRequest {
     pub notes: Option<String>,
     pub tags: Option<Vec<String>>,
     pub reminder_times: Option<Vec<String>>,
-    
+
     /// Pill identification (Phase 2.8 - optional)
     #[serde(rename = "pill_identification")]
     pub pill_identification: Option<PillIdentification>,
@@ -216,13 +216,19 @@ impl MedicationRepository {
     pub fn new(collection: Collection<Medication>) -> Self {
         Self { collection }
     }
-    
-    pub async fn create(&self, medication: Medication) -> Result<Medication, Box<dyn std::error::Error>> {
+
+    pub async fn create(
+        &self,
+        medication: Medication,
+    ) -> Result<Medication, Box<dyn std::error::Error>> {
         let _result = self.collection.insert_one(medication.clone(), None).await?;
         Ok(medication)
     }
-    
-    pub async fn find_by_user(&self, user_id: &str) -> Result<Vec<Medication>, Box<dyn std::error::Error>> {
+
+    pub async fn find_by_user(
+        &self,
+        user_id: &str,
+    ) -> Result<Vec<Medication>, Box<dyn std::error::Error>> {
         let filter = doc! { "userId": user_id };
         let mut cursor = self.collection.find(filter, None).await?;
         let mut medications = Vec::new();
@@ -231,9 +237,13 @@ impl MedicationRepository {
         }
         Ok(medications)
     }
-    
-    pub async fn find_by_user_and_profile(&self, user_id: &str, profile_id: &str) -> Result<Vec<Medication>, Box<dyn std::error::Error>> {
-        let filter = doc! { 
+
+    pub async fn find_by_user_and_profile(
+        &self,
+        user_id: &str,
+        profile_id: &str,
+    ) -> Result<Vec<Medication>, Box<dyn std::error::Error>> {
+        let filter = doc! {
             "userId": user_id,
             "profileId": profile_id
         };
@@ -244,16 +254,23 @@ impl MedicationRepository {
         }
         Ok(medications)
     }
-    
-    pub async fn find_by_id(&self, id: &ObjectId) -> Result<Option<Medication>, Box<dyn std::error::Error>> {
+
+    pub async fn find_by_id(
+        &self,
+        id: &ObjectId,
+    ) -> Result<Option<Medication>, Box<dyn std::error::Error>> {
         let filter = doc! { "_id": id };
         let medication = self.collection.find_one(filter, None).await?;
         Ok(medication)
     }
-    
-    pub async fn update(&self, id: &ObjectId, updates: UpdateMedicationRequest) -> Result<Option<Medication>, Box<dyn std::error::Error>> {
+
+    pub async fn update(
+        &self,
+        id: &ObjectId,
+        updates: UpdateMedicationRequest,
+    ) -> Result<Option<Medication>, Box<dyn std::error::Error>> {
         let mut update_doc = doc! {};
-        
+
         if let Some(name) = updates.name {
             update_doc.insert("medicationData.name", name);
         }
@@ -301,21 +318,28 @@ impl MedicationRepository {
                 update_doc.insert("pillIdentification", pill_doc);
             }
         }
-        
+
         update_doc.insert("updatedAt", mongodb::bson::DateTime::now());
-        
+
         let filter = doc! { "_id": id };
-        let medication = self.collection.find_one_and_update(filter, doc! { "$set": update_doc }, None).await?;
+        let medication = self
+            .collection
+            .find_one_and_update(filter, doc! { "$set": update_doc }, None)
+            .await?;
         Ok(medication)
     }
-    
+
     pub async fn delete(&self, id: &ObjectId) -> Result<bool, Box<dyn std::error::Error>> {
         let filter = doc! { "_id": id };
         let result = self.collection.delete_one(filter, None).await?;
         Ok(result.deleted_count > 0)
     }
-    
-    pub async fn calculate_adherence(&self, medication_id: &str, days: i64) -> Result<AdherenceStats, Box<dyn std::error::Error>> {
+
+    pub async fn calculate_adherence(
+        &self,
+        medication_id: &str,
+        days: i64,
+    ) -> Result<AdherenceStats, Box<dyn std::error::Error>> {
         // For now, return a placeholder adherence calculation
         // In a full implementation, this would query the medication_doses collection
         Ok(AdherenceStats {