chore: add .editorconfig and consistent formatting for backend projects

Adds an `.editorconfig` file with C# and project-specific conventions. Applies consistent indentation and formatting across backend handlers, runtime models, and AI services.

.idea/.idea.SpaceGame/.idea/.gitignore

@@ -0,0 +1,15 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Rider ignored files
+/contentModel.xml
+/modules.xml
+/projectSettingsUpdater.xml
+/.idea.SpaceGame.iml
+# Ignored default folder with query files
+/queries/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml
+# Editor-based HTTP Client requests
+/httpRequests/

.idea/.idea.SpaceGame/.idea/.name

@@ -0,0 +1 @@
+SpaceGame

.idea/.idea.SpaceGame/.idea/encodings.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Encoding" addBOMForNewFiles="with BOM under Windows, with no BOM otherwise" />
+</project>

.idea/.idea.SpaceGame/.idea/indexLayout.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="UserContentModel">
+    <attachedFolders />
+    <explicitIncludes />
+    <explicitExcludes />
+  </component>
+</project>

.idea/.idea.SpaceGame/.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>

apps/backend/.editorconfig

@@ -0,0 +1,54 @@
+root = true
+
+[*.{cs,csx}]
+charset = utf-8
+end_of_line = crlf
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 4
+
+# .NET/C# conventions
+dotnet_sort_system_directives_first = true
+dotnet_separate_import_directive_groups = false
+dotnet_style_qualification_for_field = false:suggestion
+dotnet_style_qualification_for_property = false:suggestion
+dotnet_style_qualification_for_method = false:suggestion
+dotnet_style_qualification_for_event = false:suggestion
+dotnet_style_predefined_type_for_locals_parameters_members = true:suggestion
+dotnet_style_predefined_type_for_member_access = true:suggestion
+dotnet_style_require_accessibility_modifiers = for_non_interface_members:suggestion
+dotnet_style_object_initializer = true:suggestion
+dotnet_style_collection_initializer = true:suggestion
+dotnet_style_coalesce_expression = true:suggestion
+dotnet_style_null_propagation = true:suggestion
+dotnet_style_explicit_tuple_names = true:suggestion
+dotnet_style_prefer_auto_properties = true:suggestion
+dotnet_style_prefer_collection_expression = true:suggestion
+dotnet_style_prefer_conditional_expression_over_assignment = true:suggestion
+dotnet_style_prefer_conditional_expression_over_return = true:suggestion
+
+csharp_prefer_braces = true:suggestion
+csharp_style_var_for_built_in_types = false:suggestion
+csharp_style_var_when_type_is_apparent = true:suggestion
+csharp_style_var_elsewhere = false:suggestion
+csharp_prefer_simple_using_statement = true:suggestion
+csharp_style_prefer_switch_expression = true:suggestion
+csharp_style_prefer_primary_constructors = false:silent
+csharp_new_line_before_open_brace = all
+
+[*.{csproj,props,targets,sln,slnx}]
+charset = utf-8
+end_of_line = crlf
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 2
+
+[*.{json,jsonc}]
+charset = utf-8
+end_of_line = crlf
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 2

apps/backend/Simulation/Core/SimulationProjectionService.cs

@@ -1,7 +1,7 @@
 using System.Globalization;
+using static SpaceGame.Api.Shared.Runtime.SimulationRuntimeSupport;
 using static SpaceGame.Api.Stations.Simulation.InfrastructureSimulationService;
 using static SpaceGame.Api.Stations.Simulation.StationSimulationService;
-using static SpaceGame.Api.Shared.Runtime.SimulationRuntimeSupport;
 
 namespace SpaceGame.Api.Simulation.Core;