feat: add MCP endpoint and API key management

- Add ApiKey Prisma model (SHA-256 hash, prefix, lastUsedAt) with migration
- Implement ApiKeyService (create, list, delete, verify)
- Extend requireAuth middleware to accept sk_-prefixed API keys alongside JWTs
- Add GET/POST /api-keys routes for creating and revoking keys
- Add stateless Streamable HTTP MCP server at POST/GET /mcp exposing all 20
  time-tracking tools (clients, projects, time entries, timer, statistics,
  client targets and corrections)
- Frontend: ApiKey types, apiKeys API module, useApiKeys hook
- Frontend: ApiKeysPage with key table, one-time raw-key reveal modal, and
  inline revoke confirmation
- Wire /api-keys route and add API Keys link to Management dropdown in Navbar

backend/src/index.ts

@@ -13,6 +13,8 @@ import projectRoutes from "./routes/project.routes";
 import timeEntryRoutes from "./routes/timeEntry.routes";
 import timerRoutes from "./routes/timer.routes";
 import clientTargetRoutes from "./routes/clientTarget.routes";
+import apiKeyRoutes from "./routes/apiKey.routes";
+import mcpRoutes from "./routes/mcp.routes";
 
 async function main() {
   // Validate configuration
@@ -70,6 +72,8 @@ async function main() {
   app.use("/time-entries", timeEntryRoutes);
   app.use("/timer", timerRoutes);
   app.use("/client-targets", clientTargetRoutes);
+  app.use("/api-keys", apiKeyRoutes);
+  app.use("/mcp", mcpRoutes);
 
   // Error handling
   app.use(notFoundHandler);