docs: add LOCAL_TESTING.md for SQL operations in local development

Author: idoshamun

docs/LOCAL_TESTING.md

@@ -0,0 +1,60 @@
+# Local Testing Operations
+
+Common SQL queries and operations for local development and testing.
+
+## Opportunity & Recruiter Testing
+
+### Fake Payment for an Opportunity
+
+Payment status for opportunities is tracked on the **Organization** level via the `recruiterSubscriptionFlags` column. To simulate a paid subscription:
+
+**If you know your organization ID:**
+
+```sql
+UPDATE organization
+SET "recruiterSubscriptionFlags" = jsonb_build_object(
+  'status', 'active',
+  'provider', 'paddle',
+  'subscriptionId', 'fake_sub_123',
+  'createdAt', now(),
+  'updatedAt', now(),
+  'items', jsonb_build_array(
+    jsonb_build_object('priceId', 'pri_fake_123', 'quantity', 5)
+  )
+)
+WHERE id = 'YOUR_ORGANIZATION_ID';
+```
+
+**If you know your opportunity ID:**
+
+```sql
+UPDATE organization
+SET "recruiterSubscriptionFlags" = jsonb_build_object(
+  'status', 'active',
+  'provider', 'paddle',
+  'subscriptionId', 'fake_sub_123',
+  'createdAt', now(),
+  'updatedAt', now(),
+  'items', jsonb_build_array(
+    jsonb_build_object('priceId', 'pri_fake_123', 'quantity', 5)
+  )
+)
+WHERE id = (SELECT "organizationId" FROM opportunity WHERE id = 'YOUR_OPPORTUNITY_ID');
+```
+
+**Key fields:**
+
+| Field | Description |
+|-------|-------------|
+| `status` | Must be `'active'` for payment validation to pass |
+| `provider` | Use `'paddle'` |
+| `items[].quantity` | Number of opportunity "seats" available |
+
+**To reset/remove fake payment:**
+
+```sql
+UPDATE organization
+SET "recruiterSubscriptionFlags" = '{}'
+WHERE id = 'YOUR_ORGANIZATION_ID';
+```
+