fix(stripe_fdw): add missing status column to subscriptions table

[sanskar-soni-9]

What kind of change does this PR introduce?

Bug fix.

What is the current behavior?

stripe_fdw already treats status as a pushdown qualifier for stripe.subscriptions, and docs/catalog/stripe.md recommends filtering subscriptions by id, customer, price, status — but the status column was never added to the table's column config.
As a result, where status = 'active' fails with ERROR: column "status" does not exist, even though both the code and the docs advertise it as filterable.

Closes: #317

What is the new behavior?

status text is added to the subscriptions column config and to the example in docs/catalog/stripe.md, matching the existing pattern already used for refunds.

Also the subscriptions test in tests.rs is extended to assert the new column.

Additional context

price has the same missing-column symptom (registered as a pushdown qual at stripe_fdw.rs:336, listed in the same docs note) but isn't fixable the same way — price lives nested under items.data[].price on the Stripe API object, not top-level like status, so it needs real flattening logic rather than a column-config addition. Noting it here as a follow-up, not part of this fix.

[burmecia]

Thanks for the PR!

[sanskar-soni-9]

Hi @burmecia, thanks for merging the PR!

Also as I mentioned in the PR description, price has the same problem as the status had. But its a special case as price is nested inside items array.

What do you suggest here?

1. Support price as a simple text column (populating it with the primary/first item's price) to allow the pushdown filter?
2. Or avoid mapping it to a single column because of multi-item subscriptions, and remove it from the pushdown options?

Let me know your thoughts!

[burmecia]

Hi @burmecia, thanks for merging the PR!

Also as I mentioned in the PR description, price has the same problem as the status had. But its a special case as price is nested inside items array.

What do you suggest here?

1. Support price as a simple text column (populating it with the primary/first item's price) to allow the pushdown filter?
2. Or avoid mapping it to a single column because of multi-item subscriptions, and remove it from the pushdown options?

Let me know your thoughts!

I think option 2 is better as subscription and price is essentially 1:n relationship, the query for filtering subscription by price doesn't seem semantically correct for me.