Remove obsolete scripts and configuration files for self-hosting and database migrations

- Deleted `pnpm-workspace.yaml` as it is no longer needed.
- Removed `apply-migrations.sh` script that handled database migrations.
- Eliminated `generate-full-stack-env.mjs` script for environment variable generation.
- Deleted `selfhost-backup.sh` script for creating backups of the self-hosted environment.
- Removed `selfhost-doctor.sh` script for health checks of the self-hosted services.
- Deleted `selfhost-restore.sh` script for restoring backups in the self-hosted environment.

.dockerignore

@@ -1,47 +0,0 @@
-# Dependencies
-node_modules
-npm-debug.log*
-yarn-debug.log*
-pnpm-debug.log*
-
-# Next.js
-.next
-out
-dist
-build
-
-# Environment files (will be injected at runtime)
-.env*
-!.env.example
-
-# Version control
-.git
-.gitattributes
-
-# IDE
-.vscode
-.idea
-
-# OS
-.DS_Store
-Thumbs.db
-
-# Python (legacy)
-__pycache__
-*.py
-*.pyw
-requirements.txt
-
-# Docs & Scripts
-docs
-*.md
-!README.md
-*.bat
-ROADMAP.md
-
-# Supabase (not needed in Docker image)
-supabase
-
-# Artifacts / Gemini
-.artifacts
-.gemini