Change Drip tags without stray typos or surprises

**Objective:** On the Drip subscriber `{email}`, add tag `{add-tag}` and remove tag `{remove-tag}` (either may be blank, not both).

**Step 1: Read the subscriber**

Call `drip-get-subscriber` with `email` = `{email}` and note their current tags. If no one matches, stop.

**Step 2: Check the tags**

* For `{add-tag}`: call `drip-get-tag` with `tag` = `{add-tag}`. If it does not exist, call again with `tag.contains` and show close matches; adding a new spelling creates a new tag, so ask whether a close match was meant.
* For `{remove-tag}`: confirm the subscriber actually carries it, matching exactly. If not, say so and skip that removal.
* If the subscriber already has `{add-tag}`, skip that addition.

**Step 3: Confirm**

Show current tags and the resulting tags. Wait for the user to say yes.

**Step 4: Write and verify**

Call `drip-add-subscriber-tag` and/or `drip-remove-subscriber-tag` once each, as needed, with `email` = `{email}`. Then re-read with `drip-get-subscriber` and report the final tag list.

**Rules & Guidelines:**

* Tags can trigger Drip automations. Mention this in the confirmation.
* Do not call any other write tool.

**Validation:**

* If both `{add-tag}` and `{remove-tag}` are blank, ask what to change.