Refactor configuration and security features for improved development experience

- Updated the .env.example file to reflect a development environment setup with enhanced secret key requirements and local host settings.
- Modified the Docker Compose configuration to enhance security with read-only settings and no-new-privileges options.
- Updated requirements.txt to pin package versions for better dependency management.
- Enhanced the FastAPI application to include dynamic OpenAPI and documentation URLs based on the environment.
- Implemented session versioning in JWT tokens to improve security and user session management.
- Added new validation for user roles and password strength in schemas.
- Improved email sending logic to handle recipient lists more robustly and added logging for SMTP operations.
- Updated dashboard and profile templates to reflect new features and improve user experience.

app/core/email_utils.py

@@ -0,0 +1,16 @@
+from pydantic import EmailStr, TypeAdapter
+
+_email_adapter = TypeAdapter(EmailStr)
+
+
+def parse_recipient_list(raw: str) -> list[str]:
+    recipients: list[str] = []
+    for part in raw.split(","):
+        addr = part.strip()
+        if not addr:
+            continue
+        if any(ch in addr for ch in ("\n", "\r", "\0")):
+            raise ValueError(f"Ungültige E-Mail-Adresse: {addr!r}")
+        _email_adapter.validate_python(addr)
+        recipients.append(addr)
+    return recipients