refactor: extract shared RepoTab type to types.ts, remove duplication

RepoTab was defined identically in both DashboardHome.tsx and
RepoDetailView.tsx. Moved to types.ts as single source of truth.

Author: DevanshuNEU

frontend/src/components/dashboard/DashboardHome.tsx

@@ -16,8 +16,7 @@ import { GitHubRepoSelector } from '../GitHubRepoSelector'
 import { IndexingProgressModal } from '../IndexingProgressModal'
 import { UpgradeLimitModal } from '../UpgradeLimitModal'
 import type { GitHubRepo } from '../../hooks/useGitHubRepos'
-
-type RepoTab = 'overview' | 'search' | 'dependencies' | 'insights' | 'impact'
+import type { RepoTab } from '../../types'
 
 export function DashboardHome() {
   const { session } = useAuth()

frontend/src/components/dashboard/RepoDetailView.tsx

@@ -17,11 +17,9 @@ import { DependencyGraph } from '../DependencyGraph'
 import { RepoOverview } from '../RepoOverview'
 import { StyleInsights } from '../StyleInsights'
 import { ImpactAnalyzer } from '../ImpactAnalyzer'
-import type { Repository } from '../../types'
+import type { Repository, RepoTab } from '../../types'
 import { API_URL } from '../../config/api'
 
-type RepoTab = 'overview' | 'search' | 'dependencies' | 'insights' | 'impact'
-
 const TABS = [
   { id: 'overview', label: 'Overview', icon: LayoutDashboard },
   { id: 'search', label: 'Search', icon: Search },

frontend/src/types.ts

@@ -17,3 +17,5 @@ export interface SearchResult {
   line_start: number
   line_end: number
 }
+
+export type RepoTab = 'overview' | 'search' | 'dependencies' | 'insights' | 'impact'