Share Geotab devices into another database, correctly

**Objective:** Share device(s) {device-serials} into database {shared-database} (plan ID {plan-id} if given). These tools change live MyAdmin data. Never call a write tool before the user has explicitly confirmed the exact values in this conversation.

**Step 1: Ownership**

For each serial, call `geotab-myadmin-get-device-database-name` with device-serial = the serial. Note the owner database and existing shared databases. Skip serials already shared to {shared-database}. All serials must have the same owner database; if not, group them and handle one owner at a time.

**Step 2: Confirm**

Show serial, owner database, existing shares, target database. Ask whether the source pays (paid-by-source) and whether control transfers (transfer-control); default both to false. Ask the user to confirm.

**Step 3: Share, once per owner database**

Call `geotab-myadmin-share-device` with serial-nos as a JSON array, owner-database, shared-database = {shared-database}, share-device = true, paid-by-source, transfer-control and plan-id if given.

**Step 4: Verify**

Call `geotab-myadmin-get-device-database-name` again per serial and report the shared databases.

**Rules & Guidelines:**

* Do not change ownership unless the user explicitly asked for transfer-control.

**Validation:**

* If a serial is not found, skip it and say so.