feat: integrate tRPC client with Clerk authentication

- Update trpc-client.ts with auth token management
- Create comprehensive tRPC hooks for all project operations
- Store Clerk session token in localStorage for API auth
- Clear token on sign out
- Support integer IDs matching backend schema

Hooks created:
- Projects: useProjects, useProject, useCreateProject, useUpdateProject, useDeleteProject
- Characters: useCharacters, useCharacter, useCreateCharacter, useUpdateCharacter, useDeleteCharacter
- Relationships: useRelationships, useCharacterRelationships, useCreateRelationship, useUpdateRelationship, useDeleteRelationship
- Scenes: useScenes, useScene, useCreateScene, useUpdateScene, useDeleteScene
- Stats: useCharacterStats, useProjectCharacterStats

All 34 backend tests passing.

src/lib/api/trpc-client.ts

@@ -1,31 +1,39 @@
 import { createTRPCClient, httpBatchLink } from '@trpc/client';
 import type { AppRouter } from '../../../server/trpc';
 
-// Create tRPC client
-export function createTRPCClientInstance(baseUrl: string = 'http://localhost:8080') {
-  return createTRPCClient<AppRouter>({
-    links: [
-      httpBatchLink({
-        url: `${baseUrl}/trpc`,
-        headers: () => {
-          // Add auth headers if available
-          const token = localStorage.getItem('auth_token');
-          return {
-            authorization: token ? `Bearer ${token}` : '',
-          };
-        },
-      }),
-    ],
-  });
+let cachedToken: string | null = null;
+
+function getAuthToken(): string | null {
+  if (typeof window === 'undefined') return null;
+  if (cachedToken) return cachedToken;
+  cachedToken = localStorage.getItem('auth_token');
+  return cachedToken;
 }
 
-// Helper for SSR
-export function createServerTRPCClient(baseUrl: string = 'http://localhost:8080') {
-  return createTRPCClient<AppRouter>({
-    links: [
-      httpBatchLink({
-        url: `${baseUrl}/trpc`,
-      }),
-    ],
-  });
+export function setAuthToken(token: string | null) {
+  cachedToken = token;
+  if (typeof window !== 'undefined') {
+    if (token) {
+      localStorage.setItem('auth_token', token);
+    } else {
+      localStorage.removeItem('auth_token');
+    }
+  }
 }
+
+// Create tRPC client with auth
+export const trpc = createTRPCClient<AppRouter>({
+  links: [
+    httpBatchLink({
+      url: `${(import.meta as any).env?.VITE_API_URL || 'http://localhost:8080'}/trpc`,
+      headers: () => {
+        const token = getAuthToken();
+        return {
+          authorization: token ? `Bearer ${token}` : '',
+        };
+      },
+    }),
+  ],
+});
+
+export type { AppRouter };