Add next-auth with OIDC

[SferaDev]

No description provided.

[Copilot]

PR Overview

This PR introduces NextAuth with OIDC support using Keycloak, while consolidating environment variable management for both client and server contexts. Key changes include:

• Adding a new server-side environment configuration (server.ts) that merges client and server variables.
• Implementing authentication endpoints and middleware using NextAuth with an OIDC provider.
• Updating dependency lock files to include the new next-auth release and its associated peer dependencies, and removing legacy env files.

Reviewed Changes

File	Description
apps/dbagent/src/lib/env/server.ts	New unified server environment configuration that merges client and server variables.
apps/dbagent/src/auth.ts	Configures NextAuth with an OIDC provider for Keycloak.
apps/dbagent/src/middleware.ts	Exports NextAuth's auth handler as middleware.
apps/dbagent/src/app/api/auth/[...nextauth]/route.ts	Implements API route handlers for authentication.
pnpm-lock.yaml	Updates dependency versions and introduces new packages related to next-auth.
apps/dbagent/src/lib/notifications/slack-webhook.ts	Changes environment variable import from a general env to the client environment.
apps/dbagent/src/lib/env/client.ts	Minor cleanup in the client environment file.
apps/dbagent/src/lib/db/db.ts	Adjusts env import to use the unified server configuration.
apps/dbagent/src/lib/monitoring/scheduler.ts	Adjusts env import to use the unified server configuration.
apps/dbagent/src/lib/env/scheduler.ts	Removes redundant scheduler environment configuration.
apps/dbagent/src/lib/env/db.ts	Removes duplicate database environment configuration.

Copilot reviewed 12 out of 12 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (1)

apps/dbagent/src/lib/notifications/slack-webhook.ts:4

• The slack-webhook module might be better served using the secure server environment instead of the client environment to prevent potential exposure of sensitive credentials. Consider importing from '../env/server' if this code executes on the server.

import { env } from '../env/client';

[tsg]

Nice, works well in my testing.