Fix API contract mismatches with Go backend

- Document.purchasePrice: String? → Double? (matches Go decimal.Decimal)
- TaskTemplate: add regionId/regionName (Go returns these, KMM was ignoring)
- TaskResponse.completions: add comment explaining separate fetch pattern
- Document: add comments clarifying fileUrl vs mediaUrl usage

composeApp/src/commonMain/kotlin/com/tt/honeyDue/models/CustomTask.kt

@@ -55,6 +55,9 @@ data class TaskResponse(
     @SerialName("parent_task_id") val parentTaskId: Int? = null,
     @SerialName("completion_count") val completionCount: Int = 0,
     @SerialName("kanban_column") val kanbanColumn: String? = null, // Which kanban column this task belongs to
+    // Note: Go API does not return completions inline with TaskResponse.
+    // Completions are fetched separately via the completions endpoint.
+    // This field defaults to emptyList() and is only populated client-side after a separate fetch.
     val completions: List<TaskCompletionResponse> = emptyList(),
     @SerialName("created_at") val createdAt: String,
     @SerialName("updated_at") val updatedAt: String

composeApp/src/commonMain/kotlin/com/tt/honeyDue/models/Document.kt

@@ -33,8 +33,12 @@ data class Document(
     val title: String,
     @SerialName("document_type") val documentType: String,
     val description: String? = null,
-    @SerialName("file_url") val fileUrl: String? = null, // URL to the file
+    // fileUrl: raw storage path (internal). Not included in Go DocumentResponse DTO —
-    @SerialName("media_url") val mediaUrl: String? = null, // Authenticated endpoint: /api/media/document/{id}
+    // will always be null from the API. Kept for backward compatibility; prefer mediaUrl.
+    @SerialName("file_url") val fileUrl: String? = null,
+    // mediaUrl: authenticated endpoint clients should use (e.g. /api/media/document/{id}).
+    // This is the URL the Go API actually returns for document access.
+    @SerialName("media_url") val mediaUrl: String? = null,
     @SerialName("file_name") val fileName: String? = null,
     @SerialName("file_size") val fileSize: Int? = null,
     @SerialName("mime_type") val mimeType: String? = null,
@@ -43,7 +47,7 @@ data class Document(
     @SerialName("serial_number") val serialNumber: String? = null,
     val vendor: String? = null,
     @SerialName("purchase_date") val purchaseDate: String? = null,
-    @SerialName("purchase_price") val purchasePrice: String? = null,
+    @SerialName("purchase_price") val purchasePrice: Double? = null,
     @SerialName("expiry_date") val expiryDate: String? = null,
     // Relationships
     @SerialName("residence_id") val residenceId: Int? = null,
@@ -87,7 +91,7 @@ data class DocumentCreateRequest(
     @SerialName("serial_number") val serialNumber: String? = null,
     val vendor: String? = null,
     @SerialName("purchase_date") val purchaseDate: String? = null,
-    @SerialName("purchase_price") val purchasePrice: String? = null,
+    @SerialName("purchase_price") val purchasePrice: Double? = null,
     @SerialName("expiry_date") val expiryDate: String? = null,
     // Relationships
     @SerialName("residence_id") val residenceId: Int,
@@ -106,7 +110,7 @@ data class DocumentUpdateRequest(
     @SerialName("serial_number") val serialNumber: String? = null,
     val vendor: String? = null,
     @SerialName("purchase_date") val purchaseDate: String? = null,
-    @SerialName("purchase_price") val purchasePrice: String? = null,
+    @SerialName("purchase_price") val purchasePrice: Double? = null,
     @SerialName("expiry_date") val expiryDate: String? = null,
     // Relationships
     @SerialName("task_id") val taskId: Int? = null

composeApp/src/commonMain/kotlin/com/tt/honeyDue/models/TaskTemplate.kt

@@ -20,7 +20,9 @@ data class TaskTemplate(
     @SerialName("icon_android") val iconAndroid: String = "",
     val tags: List<String> = emptyList(),
     @SerialName("display_order") val displayOrder: Int = 0,
-    @SerialName("is_active") val isActive: Boolean = true
+    @SerialName("is_active") val isActive: Boolean = true,
+    @SerialName("region_id") val regionId: Int? = null,
+    @SerialName("region_name") val regionName: String? = null
 ) {
     /**
      * Human-readable frequency display