setting up Activiti BPMN Workflow Engine with Spring Boot

Controls how Activiti handles its database tables on startup.
Options:
- true -- Default. Creates or updates tables automatically if missing. ✅ Good for development.
- false -- Disables auto-update. Throws an error if tables are missing or version mismatch. ❌ For production.
- create_drop -- Creates tables on start and drops them on shutdown. ⚠️ Risky, only for testing.
- drop-create -- Drops existing tables and creates new ones every time app starts.

Defines how much history Activiti saves.
Options:
- none -- No history (best performance).
- activity -- Saves basic activity instance data.
- audit -- Adds task info like who did what.
- full -- Saves everything , including variables and execution details. ✅ Best for debugging/auditing.

Whether to automatically scan and deploy BPMN process files from resources/processes/.
false -- You must manually deploy processes (e.g., via code or REST).
✅ Useful when you don't want automatic redeployments (e.g., in production).

Controls deployment conflict handling:
- default -- May fail if process definition is already deployed.
- single-resource -- Deploys each file separately.
- never-fail -- Ignores duplicate deployments, avoids errors.
✅ Safer option to prevent deployment exceptions during startup.

Setting	Value	Meaning
`database-schema-update`	`true`	Auto-create/update tables
`db-history-used`	`true`	Enable history tables
`history-level`	`full`	Save full execution history
`check-process-definitions`	`false`	Don't auto-load BPMN files
`deployment-mode`	`never-fail`	Avoid deployment errors on startup
`async-executor-activate`	`false`	Don't start async job processor