Improve sidebar layout: center Projects title, fix padding, add method chips

- Center "Projects" label in sidebar headerbar via title-widget property
- Fix asymmetric request list margins (margin-start 12→6, add margin-end 6)
- Replace dim method labels with colored chips (GET/POST/PUT/PATCH/DELETE)

src/main-window.ui

@@ -43,22 +43,20 @@
             <!-- Sidebar Header Bar -->
             <child type="top">
               <object class="AdwHeaderBar">
-                <property name="show-title">False</property>
                 <property name="show-end-title-buttons">False</property>
                 <property name="show-start-title-buttons">False</property>
-                <child type="start">
-                  <object class="GtkWindowControls">
-                    <property name="side">start</property>
-                  </object>
-                </child>
-                <child type="start">
+                <property name="title-widget">
                   <object class="GtkLabel">
                     <property name="label">Projects</property>
-                    <property name="margin-start">6</property>
                     <style>
                       <class name="title"/>
                     </style>
                   </object>
+                </property>
+                <child type="start">
+                  <object class="GtkWindowControls">
+                    <property name="side">start</property>
+                  </object>
                 </child>
                 <child type="end">
                   <object class="GtkButton" id="add_project_button">

src/widgets/project-item.ui

@@ -72,7 +72,8 @@
 
         <child>
           <object class="GtkListBox" id="requests_listbox">
-            <property name="margin-start">12</property>
+            <property name="margin-start">6</property>
+            <property name="margin-end">6</property>
             <style>
               <class name="navigation-sidebar"/>
             </style>

src/widgets/request-item.ui

@@ -11,10 +11,9 @@
 
     <child>
       <object class="GtkLabel" id="method_label">
-        <property name="width-chars">6</property>
+        <property name="xalign">0.5</property>
         <style>
-          <class name="caption"/>
-          <class name="dim-label"/>
+          <class name="method-chip"/>
         </style>
       </object>
     </child>

src/widgets/request_item.py

@@ -20,6 +20,14 @@
 
 from gi.repository import Gtk, GObject
 
+_METHOD_CSS = {
+    'GET':    'accent',
+    'POST':   'success',
+    'PUT':    'warning',
+    'PATCH':  'warning',
+    'DELETE': 'error',
+}
+
 
 @Gtk.Template(resource_path='/cz/bugsy/roster/widgets/request-item.ui')
 class RequestItem(Gtk.Box):
@@ -38,7 +46,9 @@ class RequestItem(Gtk.Box):
     def __init__(self, saved_request):
         super().__init__()
         self.saved_request = saved_request
-        self.method_label.set_text(saved_request.request.method)
+        method = saved_request.request.method
+        self.method_label.set_text(method)
+        self.method_label.add_css_class(_METHOD_CSS.get(method, 'dim-label'))
         self.name_label.set_text(saved_request.name)
 
         # Add click gesture for loading

src/window.py

@@ -203,6 +203,18 @@ class RosterWindow(Adw.ApplicationWindow):
                 color: @accent_color;
                 font-weight: 600;
             }
+
+            /* Method chips in sidebar request list */
+            .method-chip {
+                border-radius: 4px;
+                padding: 1px 5px;
+                font-size: 0.72em;
+                font-weight: 700;
+            }
+            .method-chip.accent  { background-color: alpha(@accent_bg_color,  0.18); }
+            .method-chip.success { background-color: alpha(@success_bg_color, 0.18); }
+            .method-chip.warning { background-color: alpha(@warning_bg_color, 0.18); }
+            .method-chip.error   { background-color: alpha(@error_bg_color,   0.18); }
         """)
 
         Gtk.StyleContext.add_provider_for_display(