feat(sidebar): add P key toggle for project dropdown

Fixed P key behavior to toggle the project dropdown on/off. Added keyboard handler to detect P key when dropdown is open and close it. Also enhanced theme system with action button colors and improved Kanban card styling consistency.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4 <noreply@anthropic.com>

app/src/components/layout/sidebar.tsx

@@ -178,7 +178,7 @@ export function Sidebar() {
     [projects, setCurrentProject]
   );
 
-  // Handle number key presses when project picker is open
+  // Handle keyboard events when project picker is open
   useEffect(() => {
     if (!isProjectPickerOpen) return;
 
@@ -189,6 +189,10 @@ export function Sidebar() {
         selectProjectByNumber(num);
       } else if (event.key === "Escape") {
         setIsProjectPickerOpen(false);
+      } else if (event.key.toLowerCase() === "p") {
+        // Toggle off when P is pressed while dropdown is open
+        event.preventDefault();
+        setIsProjectPickerOpen(false);
       }
     };
 
@@ -218,8 +222,8 @@ export function Sidebar() {
     if (projects.length > 0) {
       shortcuts.push({
         key: ACTION_SHORTCUTS.projectPicker,
-        action: () => setIsProjectPickerOpen(true),
-        description: "Open project picker",
+        action: () => setIsProjectPickerOpen((prev) => !prev),
+        description: "Toggle project picker",
       });
     }