API owners should have implicit access without requiring a subscription

[spinoDev]

-- Problem

Currently, API creators must manually subscribe to their own APIs before they can access them through the gateway.

Since the creator is expected to test and consume their own API, this adds an unnecessary step.

-- Expected Behavior

When a user publishes an API:

• An active subscription is automatically created for the owner.
• An API key is generated for that subscription.
• The owner can immediately access the API through the gateway.
• The owner cannot create another subscription for the same API.

-- Acceptance Criteria

• Publishing an API automatically creates an active subscription for the owner.
• An API key is generated for the owner's subscription.
• The owner can successfully invoke the API using the generated API key.
• Duplicate subscriptions for the owner are prevented.
• Existing subscription flow for other users remains unchanged.

-- Labels

enhancement
subscriptions
gateway