Fixes#13735
### What
This Pull Request introduces new database migrations to remove multiple redundant indexes across several core modules, including product, cart, order, customer, and inventory.
### Why
As detailed in issue #13735, a fresh Medusa installation produces numerous "Duplicate Index" warnings. These legacy indexes add unnecessary write overhead and provide no performance benefit. This PR cleans up the schema to resolve these warnings and improve database health.
### How
I have added one new, reversible migration file for each of the five affected modules:
- `@medusajs/product`
- `@medusajs/cart`
- `@medusajs/order`
- `@medusajs/customer`
- `@medusajs/inventory`
Each migration's `up()` method safely drops the older, redundant index, and its `down()` method re-creates it, ensuring the change is fully reversible and non-destructive.
### Testing
I have tested these migrations by following the local development workflow outlined in the `CONTRIBUTING.md` guide.
1. **Setup:**
* Cloned my forked Medusa repository locally .
* Created a separate, fresh test project using `npx create-medusa-app@latest my-medusa-store`.
* The test project's PostgreSQL database, which already contained the schema with the duplicate indexes.
2. **Linking Local Source Code:**
* In the test project's `package.json`, I modified all `@medusajs/*` dependencies and resolutions to point to the local packages in my forked repository (e.g., `"@medusajs/product": "file:../medusa/packages/modules/product"`).
* From the test project's directory, I ran `yarn install` to link the local, modified Medusa source code into its `node_modules`.
3. **Build & Migration:**
* Inside my forked Medusa repository, I ran `yarn build` to compile the new TypeScript migration files.
* From the root of the **test project**, I then executed the migration command: `npx medusa migration run`.
4. **Verification:**
* The command successfully identified and ran only the new migration files I had created.
* I also confirmed via direct SQL queries that the old, redundant indexes were correctly dropped from all affected tables (`product_collection`, `customer_group`, etc.).
* feat: Custom line items
* fix tests
* fix migration
* Allow custom items in update line item workflow
* throw if line item doesn't have a price
* minor things
* wip
* fix flows
* fix test
* add default
* add to type
