feat(07-01): create config/ folder and YAML example files

- Added backend.yaml.example with AI, DB, auth, and logging schema
- Added frontend.yaml.example with API and feature flag schema
- Added network.yaml.example with ports and SSL schema
- Added docker.yaml.example with resource and volume schema
- Added secrets.yaml.example as a template for sensitive data
- All files include comprehensive comments documenting every variable

config/backend.yaml.example

@@ -0,0 +1,110 @@
+# =============================================================================
+# TFM aInventory - Backend Configuration Schema (v1.12.0)
+# =============================================================================
+# Purpose: Configuration for the FastAPI backend, database, AI, and logging.
+# Load order: system environment variables > config/backend.yaml > code defaults.
+# Required/Optional: Most are optional; defaults in code provide sensible behavior.
+# =============================================================================
+
+# --- Database & Storage ---
+database:
+  # Path to SQLite database file (relative to backend/ folder)
+  # Default: data/inventory.db
+  # Environment: BACKEND_DATABASE_SQLITE_PATH
+  sqlite_path: "data/inventory.db"
+
+  # Keep database logs for performance auditing?
+  # Default: true
+  # Environment: BACKEND_DATABASE_WAL_MODE
+  wal_mode: true
+
+  # How many days of audit logs to keep?
+  # Default: 30
+  # Environment: BACKEND_DATABASE_LOG_RETENTION_DAYS
+  log_retention_days: 30
+
+# --- AI & Vision Services ---
+ai:
+  # Primary provider for image OCR and classification (gemini|claude)
+  # Default: gemini
+  # Environment: BACKEND_AI_PRIMARY_AI_PROVIDER
+  primary_ai_provider: "gemini"
+
+  # Fallback provider if primary fails
+  # Default: claude
+  # Environment: BACKEND_AI_FALLBACK_PROVIDER
+  fallback_provider: "claude"
+
+  # Gemini API Key (obtain from https://aistudio.google.com/)
+  # Environment: BACKEND_AI_GEMINI_API_KEY or GEMINI_API_KEY
+  gemini_api_key: "your-gemini-api-key"
+
+  # Claude API Key (obtain from Anthropic Console)
+  # Environment: BACKEND_AI_CLAUDE_API_KEY or CLAUDE_API_KEY
+  claude_api_key: "your-claude-api-key"
+
+# --- Authentication & LDAP ---
+auth:
+  # JWT Secret Key (min 32 chars)
+  # Generate with: openssl rand -hex 32
+  # Environment: BACKEND_AUTH_JWT_SECRET_KEY or JWT_SECRET_KEY
+  jwt_secret_key: "change_me_in_production"
+
+  # LDAP Server address (optional)
+  # Example: "ldap://192.168.1.100"
+  # Environment: BACKEND_AUTH_LDAP_SERVER
+  ldap_server: ""
+
+  # LDAP Base DN for user search
+  # Example: "dc=example,dc=com"
+  # Environment: BACKEND_AUTH_LDAP_BASE_DN
+  ldap_base_dn: ""
+
+  # Path to store hashed passwords for offline use
+  # Environment: BACKEND_AUTH_PASSWORD_CACHE_PATH
+  password_cache_path: "data/.passwords"
+
+# --- Logging & Diagnostics ---
+logging:
+  # Log level (DEBUG|INFO|WARNING|ERROR)
+  # Default: INFO
+  # Environment: BACKEND_LOGGING_LOG_LEVEL or LOG_LEVEL
+  log_level: "INFO"
+
+  # Log file rotation size in megabytes
+  # Default: 10
+  # Environment: BACKEND_LOGGING_LOG_ROTATION_SIZE_MB
+  log_rotation_size_mb: 10
+
+  # Number of rotated log files to keep
+  # Default: 5
+  # Environment: BACKEND_LOGGING_LOG_ROTATION_COUNT
+  log_rotation_count: 5
+
+# --- Application ---
+application:
+  # Directory for persistent data
+  # Environment: BACKEND_APPLICATION_DATA_DIR or DATA_DIR
+  data_dir: "./data"
+
+  # Directory for log files
+  # Environment: BACKEND_APPLICATION_LOGS_DIR or LOGS_DIR
+  logs_dir: "./logs"
+
+  # Comma-separated list of extra allowed CORS origins (IPs/FQDNs)
+  # Environment: BACKEND_APPLICATION_CORS_ORIGINS or EXTRA_ALLOWED_ORIGINS
+  cors_origins: "http://localhost:8917"
+
+# --- Feature Flags ---
+features:
+  # Enable AI image extraction and OCR?
+  # Default: true
+  ai_extraction_enabled: true
+
+  # Enable offline synchronization features?
+  # Default: true
+  offline_sync_enabled: true
+
+  # Enable detailed audit logging for each API request?
+  # Default: true
+  audit_logging_enabled: true