Sever: Add Sentry

[robertjdominguez]

Description

• Added comprehensive Sentry error tracking to the chat proxy server
• Updated documentation to reflect new error monitoring capabilities

Previously, the server had basic console logging but no structured error tracking. When things went sideways in production, we were flying blind.

const app = new Elysia()
  .onRequest(({ set }) => {
    // Just CORS headers, no error handling
  })

Now we have proper error monitoring with contextual information:

const app = new Elysia()
  .onError(({ error, code, set }) => {
    // Capture error in Sentry
    Sentry.captureException(error);
    
    // Return appropriate error response
    if (code === "VALIDATION") {
      set.status = 400;
      return { error: "Validation failed", message: error.message };
    }
    // ...
  })

The streaming chat handler now captures errors with request context, making debugging production issues actually possible. Added proper graceful shutdown handling to ensure error data gets flushed before the process exits.

Also fixed the CI pipeline - it was missing SENTRY_DSN and JWT_SECRET environment variables, which would cause Docker integration tests to fail silently. The kind of thing that makes you question your life choices at 2 AM.