Update admin theme/layout and refresh README details.

Align the project baseline with the latest admin interface styling and layout structure while documenting setup and usage updates in README.

apps/api/app/core/config.py

@@ -0,0 +1,54 @@
+from pydantic_settings import BaseSettings, SettingsConfigDict
+
+from app.core.install_secrets import load_install_secrets_to_env
+
+load_install_secrets_to_env()
+
+
+class Settings(BaseSettings):
+    model_config = SettingsConfigDict(env_file=".env", env_file_encoding="utf-8", extra="ignore")
+
+    database_url: str = "postgresql+psycopg://user:pass@localhost:5432/compton"
+    redis_url: str = "redis://localhost:6379/0"
+    jwt_access_secret: str = "change-me-access-secret-with-at-least-32-bytes"
+    jwt_refresh_pepper: str = "change-me-refresh-pepper-with-at-least-32-bytes"
+    jwt_access_ttl_min: int = 15
+    jwt_refresh_ttl_days: int = 30
+    enable_docs: bool = True
+    cookie_secure: bool = False
+    cors_origins: list[str] = ["http://localhost:5173"]
+    enable_rate_limit: bool = True
+    auth_lockout_attempts: int = 5
+    auth_lockout_minutes: int = 15
+    admin_initial_password: str = "Admin1234"
+    demo_user_password: str = "User1234"
+    demo_ops_password: str = "OpsAdmin1234"
+    smtp_host: str = "localhost"
+    smtp_port: int = 1025
+    smtp_user: str = ""
+    smtp_password: str = ""
+    smtp_from: str = "noreply@compton.example"
+    frontend_url: str = "http://localhost:5173"
+    public_base_url: str = "http://localhost:5173"
+    auth_token_ttl_hours: int = 1
+    email_delivery_mode: str = "smtp"
+    s3_endpoint: str = "http://localhost:9000"
+    s3_access_key: str = "minio"
+    s3_secret_key: str = "minio123"
+    s3_bucket: str = "compton"
+    s3_region: str = "us-east-1"
+    storage_mode: str = "s3"
+    avatar_max_bytes: int = 2 * 1024 * 1024
+    media_url_ttl_seconds: int = 600
+    log_level: str = "INFO"
+    audit_retention_days: int = 90
+    password_denylist_path: str = "data/security/password-denylist.txt"
+    compton_settings_path: str = "data/compton_settings.json"
+    admin_audit_log_path: str = "data/logs/admin-audit.jsonl"
+    server_log_path: str = "data/logs/server.log"
+    enable_test_routes: bool = False
+    app_env: str = "development"
+    trusted_proxy_ips: str = ""
+
+
+settings = Settings()