feat(01-01): create dual Supabase client pattern for App Router

- src/lib/supabase/client.ts: Browser client for Client Components
  - Uses createBrowserClient from @supabase/ssr
  - Reads NEXT_PUBLIC_* env vars

- src/lib/supabase/server.ts: Server client for SSR/Actions
  - Uses createServerClient from @supabase/ssr
  - Async cookies() for Next.js 15+ compatibility
  - Cookie handlers for session management
  - Try/catch in setAll for Server Component safety

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

src/lib/supabase/client.ts

@@ -0,0 +1,8 @@
+import { createBrowserClient } from '@supabase/ssr'
+
+export function createClient() {
+  return createBrowserClient(
+    process.env.NEXT_PUBLIC_SUPABASE_URL!,
+    process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!
+  )
+}

src/lib/supabase/server.ts

@@ -0,0 +1,28 @@
+import { createServerClient } from '@supabase/ssr'
+import { cookies } from 'next/headers'
+
+export async function createClient() {
+  const cookieStore = await cookies()
+
+  return createServerClient(
+    process.env.NEXT_PUBLIC_SUPABASE_URL!,
+    process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!,
+    {
+      cookies: {
+        getAll() {
+          return cookieStore.getAll()
+        },
+        setAll(cookiesToSet) {
+          try {
+            cookiesToSet.forEach(({ name, value, options }) =>
+              cookieStore.set(name, value, options)
+            )
+          } catch {
+            // The `setAll` method was called from a Server Component.
+            // This can be ignored if you have middleware refreshing user sessions.
+          }
+        },
+      },
+    }
+  )
+}