[Deep-Axe]

This pull request improves store creation safety and user feedback by adding explicit checks for store address reuse and deletion in the store admission logic. It also updates related tests and documentation to reflect these enhancements.

Store admission and error handling improvements:

• The requestStore function now checks if a store slug is already present in the database before proceeding. If the slug exists with a Deleting status, it returns a clear error message instructing the user to wait before retrying; otherwise, it reports that the store name is already in use.

Test suite and fixture updates:

• The test fixture in tests/store-requests.test.ts was extended to handle store records with slug and status, and to simulate the new slug/status check in queries. [1] [2] [3]
• A new test was added to verify that attempting to create a store with a slug marked as Deleting is blocked across teams, and that the slug can be reused once deletion is complete.
• The test count in the documentation was incremented to reflect the new test.

Documentation improvements:

• The multi-store acceptance test section in docs/verification.md was rewritten for clarity, summarizing key checks, recovery/isolation scenarios, deterministic coverage, and evidence scope.