Update .idea module configuration and simplify CSS by removing unused classes

- Updated `.idea/rosterchief.iml` to reflect module name changes and added `.venv` exclusions.
- Cleaned up `app.css` by removing unused classes and properties from legacy styles.

.idea/rosterchief.iml

@@ -4,7 +4,7 @@
     <facet type="django" name="Django">
       <configuration>
         <option name="rootFolder" value="$MODULE_DIR$" />
-        <option name="settingsModule" value="clubmanager/settings.py" />
+        <option name="settingsModule" value="rosterchief/settings.py" />
         <option name="manageScript" value="$MODULE_DIR$/manage.py" />
         <option name="environment" value="&lt;map/&gt;" />
         <option name="doNotUseTestRunner" value="false" />
@@ -14,7 +14,11 @@
   </component>
   <component name="NewModuleRootManager">
     <content url="file://$MODULE_DIR$">
-      <sourceFolder url="file://$MODULE_DIR$" />
+      <sourceFolder url="file://$MODULE_DIR$" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/.venv" />
+    </content>
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$" isTestSource="false" />
       <excludeFolder url="file://$MODULE_DIR$/.venv" />
     </content>
     <orderEntry type="jdk" jdkName="uv (ClubManager) (3)" jdkType="Python SDK" />