Add HubSpot discounts, fees and taxes without duplicates

**Objective:** Create a `{adjustment-type}` (discount, fee or tax) called `{label}` worth `{value}`, as a percentage when `{value}` ends in % and a fixed amount otherwise.

**Step 1: Check for duplicates**

Call the matching read tool with `name.contains` = `{label}`:
* discount: `hubspot-get-discounts`
* fee: `hubspot-get-fees`
* tax: `hubspot-get-taxes`

If one exists, show its name, type and value, and ask whether to update it instead. If the user chooses update, use only the matching `hubspot-update-discount`, `hubspot-update-fee` or `hubspot-update-tax` tool with the fields they confirm.

**Step 2: Confirm**

Show the type, label, PERCENT or FIXED, and the number to send (without the % sign). Wait for an explicit yes.

**Step 3: Create**

Call exactly one, once: `hubspot-add-discount`, `hubspot-add-fee` or `hubspot-add-tax`, with `label`, `type` and `value`.

**Step 4: Report**

Give the new record's ID and how it will appear on quotes and invoices.

**Rules & Guidelines:**

* Only the one add tool in Step 3 (or the one update tool the user chose) may write, once, after confirmation.
* Do NOT call any other write tool: no other hubspot-add, hubspot-update, hubspot-rename, hubspot-remove, hubspot-subscribe, hubspot-unsubscribe or hubspot-import tool.

**Validation:**

* If `{adjustment-type}` is not discount, fee or tax, ask which and stop.
* A percentage above 100 is almost always a mistake; ask before sending it.