feat: [US-015] - Rename project

Add rename functionality to project cards on the dashboard:
- Edit/rename icon button on each project card (visible on hover)
- Modal dialog with project name input field
- Supabase update for project name
- Real-time UI update without page reload
- Success toast notification after rename
- Enter key support for quick rename
- Error handling and display

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/components/ProjectCard.tsx

@@ -9,6 +9,7 @@ interface ProjectCardProps {
   name: string
   updatedAt: string
   onDelete: (id: string) => void
+  onRename: (id: string, newName: string) => void
 }
 
 function formatDate(dateString: string): string {
@@ -27,9 +28,14 @@ export default function ProjectCard({
   name,
   updatedAt,
   onDelete,
+  onRename,
 }: ProjectCardProps) {
   const [showDeleteDialog, setShowDeleteDialog] = useState(false)
   const [isDeleting, setIsDeleting] = useState(false)
+  const [showRenameDialog, setShowRenameDialog] = useState(false)
+  const [isRenaming, setIsRenaming] = useState(false)
+  const [newName, setNewName] = useState(name)
+  const [renameError, setRenameError] = useState<string | null>(null)
   const router = useRouter()
 
   const handleCardClick = () => {
@@ -65,15 +71,80 @@ export default function ProjectCard({
     }
   }
 
+  const handleRenameClick = (e: React.MouseEvent) => {
+    e.stopPropagation()
+    setNewName(name)
+    setRenameError(null)
+    setShowRenameDialog(true)
+  }
+
+  const handleConfirmRename = async () => {
+    if (!newName.trim()) {
+      setRenameError('Project name cannot be empty')
+      return
+    }
+
+    if (newName.trim() === name) {
+      setShowRenameDialog(false)
+      return
+    }
+
+    setIsRenaming(true)
+    setRenameError(null)
+
+    const supabase = createClient()
+    const { error } = await supabase
+      .from('projects')
+      .update({ name: newName.trim() })
+      .eq('id', id)
+
+    if (error) {
+      setIsRenaming(false)
+      setRenameError('Failed to rename project: ' + error.message)
+      return
+    }
+
+    setIsRenaming(false)
+    setShowRenameDialog(false)
+    onRename(id, newName.trim())
+  }
+
+  const handleCancelRename = () => {
+    if (!isRenaming) {
+      setShowRenameDialog(false)
+      setRenameError(null)
+    }
+  }
+
   return (
     <>
       <div
         onClick={handleCardClick}
         className="group relative cursor-pointer rounded-lg border border-zinc-200 bg-white p-6 transition-all hover:border-blue-300 hover:shadow-md dark:border-zinc-700 dark:bg-zinc-800 dark:hover:border-blue-600"
       >
+        <div className="absolute right-3 top-3 flex gap-1 opacity-0 transition-opacity group-hover:opacity-100">
+          <button
+            onClick={handleRenameClick}
+            className="rounded p-1 text-zinc-400 hover:bg-blue-100 hover:text-blue-600 dark:hover:bg-blue-900/30 dark:hover:text-blue-400"
+            title="Rename project"
+          >
+            <svg
+              className="h-5 w-5"
+              fill="none"
+              viewBox="0 0 24 24"
+              stroke="currentColor"
+            >
+              <path
+                strokeLinecap="round"
+                strokeLinejoin="round"
+                strokeWidth={2}
+                d="M11 5H6a2 2 0 00-2 2v11a2 2 0 002 2h11a2 2 0 002-2v-5m-1.414-9.414a2 2 0 112.828 2.828L11.828 15H9v-2.828l8.586-8.586z"
+              />
+            </svg>
+          </button>
           <button
             onClick={handleDeleteClick}
-          className="absolute right-3 top-3 rounded p-1 text-zinc-400 opacity-0 transition-opacity hover:bg-red-100 hover:text-red-600 group-hover:opacity-100 dark:hover:bg-red-900/30 dark:hover:text-red-400"
+            className="rounded p-1 text-zinc-400 hover:bg-red-100 hover:text-red-600 dark:hover:bg-red-900/30 dark:hover:text-red-400"
             title="Delete project"
           >
             <svg
@@ -90,6 +161,7 @@ export default function ProjectCard({
               />
             </svg>
           </button>
+        </div>
         <h2 className="pr-8 text-lg font-semibold text-zinc-900 group-hover:text-blue-600 dark:text-zinc-50 dark:group-hover:text-blue-400">
           {name}
         </h2>
@@ -155,6 +227,87 @@ export default function ProjectCard({
           </div>
         </div>
       )}
+
+      {showRenameDialog && (
+        <div className="fixed inset-0 z-50 flex items-center justify-center">
+          <div
+            className="absolute inset-0 bg-black/50"
+            onClick={handleCancelRename}
+            aria-hidden="true"
+          />
+          <div className="relative w-full max-w-md rounded-lg bg-white p-6 shadow-xl dark:bg-zinc-800">
+            <div className="flex items-start gap-4">
+              <div className="flex h-10 w-10 shrink-0 items-center justify-center rounded-full bg-blue-100 dark:bg-blue-900/30">
+                <svg
+                  className="h-5 w-5 text-blue-600 dark:text-blue-400"
+                  fill="none"
+                  viewBox="0 0 24 24"
+                  stroke="currentColor"
+                >
+                  <path
+                    strokeLinecap="round"
+                    strokeLinejoin="round"
+                    strokeWidth={2}
+                    d="M11 5H6a2 2 0 00-2 2v11a2 2 0 002 2h11a2 2 0 002-2v-5m-1.414-9.414a2 2 0 112.828 2.828L11.828 15H9v-2.828l8.586-8.586z"
+                  />
+                </svg>
+              </div>
+              <div className="flex-1">
+                <h3 className="text-lg font-semibold text-zinc-900 dark:text-zinc-50">
+                  Rename Project
+                </h3>
+                <div className="mt-4">
+                  <label
+                    htmlFor="project-name"
+                    className="block text-sm font-medium text-zinc-700 dark:text-zinc-300"
+                  >
+                    Project Name
+                  </label>
+                  <input
+                    type="text"
+                    id="project-name"
+                    value={newName}
+                    onChange={(e) => setNewName(e.target.value)}
+                    onKeyDown={(e) => {
+                      if (e.key === 'Enter' && !isRenaming) {
+                        handleConfirmRename()
+                      }
+                    }}
+                    autoFocus
+                    disabled={isRenaming}
+                    className="mt-1 block w-full rounded-md border border-zinc-300 bg-white px-3 py-2 text-zinc-900 placeholder-zinc-400 shadow-sm focus:border-blue-500 focus:outline-none focus:ring-1 focus:ring-blue-500 disabled:cursor-not-allowed disabled:opacity-50 dark:border-zinc-600 dark:bg-zinc-700 dark:text-zinc-50 dark:placeholder-zinc-500 dark:focus:border-blue-400 dark:focus:ring-blue-400"
+                    placeholder="Enter project name"
+                  />
+                  {renameError && (
+                    <p className="mt-2 text-sm text-red-600 dark:text-red-400">
+                      {renameError}
+                    </p>
+                  )}
+                </div>
+              </div>
+            </div>
+
+            <div className="mt-6 flex justify-end gap-3">
+              <button
+                type="button"
+                onClick={handleCancelRename}
+                disabled={isRenaming}
+                className="rounded-md border border-zinc-300 bg-white px-4 py-2 text-sm font-medium text-zinc-700 transition-colors hover:bg-zinc-50 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:ring-offset-2 disabled:cursor-not-allowed disabled:opacity-50 dark:border-zinc-600 dark:bg-zinc-700 dark:text-zinc-300 dark:hover:bg-zinc-600 dark:focus:ring-offset-zinc-800"
+              >
+                Cancel
+              </button>
+              <button
+                type="button"
+                onClick={handleConfirmRename}
+                disabled={isRenaming}
+                className="rounded-md bg-blue-600 px-4 py-2 text-sm font-medium text-white transition-colors hover:bg-blue-700 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:ring-offset-2 disabled:cursor-not-allowed disabled:opacity-50 dark:focus:ring-offset-zinc-800"
+              >
+                {isRenaming ? 'Renaming...' : 'Rename'}
+              </button>
+            </div>
+          </div>
+        </div>
+      )}
     </>
   )
 }

src/components/ProjectList.tsx

@@ -26,6 +26,13 @@ export default function ProjectList({ initialProjects }: ProjectListProps) {
     setToast({ message: 'Project deleted successfully', type: 'success' })
   }, [])
 
+  const handleRename = useCallback((id: string, newName: string) => {
+    setProjects((prev) =>
+      prev.map((p) => (p.id === id ? { ...p, name: newName } : p))
+    )
+    setToast({ message: 'Project renamed successfully', type: 'success' })
+  }, [])
+
   const handleCloseToast = useCallback(() => {
     setToast(null)
   }, [])
@@ -67,6 +74,7 @@ export default function ProjectList({ initialProjects }: ProjectListProps) {
             name={project.name}
             updatedAt={project.updated_at}
             onDelete={handleDelete}
+            onRename={handleRename}
           />
         ))}
       </div>