Add cascade delete for projects with Gitea repository cleanup

- Add deleteGiteaRepo server action to remove repos via Gitea API
- Add deleteProject function with full cascade:
  - Deletes Gitea repository if linked
  - Removes all agent_runs, messages, backlog items
  - Removes project phases, activities, recommendations
  - Finally removes the project itself
- Add ProjectSettingsMenu with delete confirmation dialog
- Add use-toast hook for notifications using sonner
- Add shadcn alert-dialog component
- Restore brand button variant after shadcn update

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

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

src/lib/supabase/projects.ts

@@ -1,4 +1,5 @@
 import { createClient } from '@/lib/supabase/client'
+import { deleteGiteaRepo } from '@/app/(dashboard)/projects/new/actions'
 import type {
   DesignPhase,
   PhaseStatus,
@@ -317,3 +318,113 @@ export async function getProjectActivities(projectId: string, limit = 20) {
     created_at: string
   }>
 }
+
+// Delete project with cascade (includes Gitea repo deletion)
+export async function deleteProject(projectId: string): Promise<{ success: boolean; error?: string }> {
+  const supabase = createClient()
+  const { data: { user } } = await supabase.auth.getUser()
+
+  if (!user) {
+    return { success: false, error: 'Not authenticated' }
+  }
+
+  try {
+    // First, get the project to check ownership and get gitea_repo
+    const { data: projectData, error: fetchError } = await supabase
+      .from('projects')
+      .select('id, user_id, gitea_repo, name')
+      .eq('id', projectId)
+      .single()
+
+    if (fetchError || !projectData) {
+      return { success: false, error: 'Project not found' }
+    }
+
+    const project = projectData as unknown as {
+      id: string
+      user_id: string
+      gitea_repo: string | null
+      name: string
+    }
+
+    // Verify ownership
+    if (project.user_id !== user.id) {
+      return { success: false, error: 'Not authorized to delete this project' }
+    }
+
+    // Extract repo name from gitea_repo URL if it exists
+    // Format: https://gitea.mylder.io/admin/repo-name
+    if (project.gitea_repo) {
+      const repoMatch = project.gitea_repo.match(/\/([^/]+)$/)
+      const repoName = repoMatch ? repoMatch[1] : null
+
+      if (repoName) {
+        const giteaResult = await deleteGiteaRepo(repoName)
+        if (!giteaResult.success) {
+          console.error('Failed to delete Gitea repo:', giteaResult.error)
+          // Continue with database deletion even if Gitea fails
+        }
+      }
+    }
+
+    // Delete related data in order (due to foreign key constraints)
+    // Delete agent_runs
+    await supabase
+      .from('agent_runs')
+      .delete()
+      .eq('project_id', projectId)
+
+    // Delete messages
+    await supabase
+      .from('messages')
+      .delete()
+      .eq('project_id', projectId)
+
+    // Delete backlog items
+    await supabase
+      .from('backlog_items')
+      .delete()
+      .eq('project_id', projectId)
+
+    // Delete project activities
+    await supabase
+      .from('project_activities')
+      .delete()
+      .eq('project_id', projectId)
+
+    // Delete AI recommendations
+    await supabase
+      .from('ai_recommendations')
+      .delete()
+      .eq('project_id', projectId)
+
+    // Delete project phases
+    await supabase
+      .from('project_phases')
+      .delete()
+      .eq('project_id', projectId)
+
+    // Delete health snapshots
+    await supabase
+      .from('project_health_snapshots')
+      .delete()
+      .eq('project_id', projectId)
+
+    // Finally, delete the project itself
+    const { error: deleteError } = await supabase
+      .from('projects')
+      .delete()
+      .eq('id', projectId)
+
+    if (deleteError) {
+      return { success: false, error: deleteError.message }
+    }
+
+    return { success: true }
+  } catch (error) {
+    return {
+      success: false,
+      error: error instanceof Error ? error.message : 'Failed to delete project'
+    }
+  }
+}