feat(tags): rename, remove-by-email, bulk delete, and subscriber filters

[imjohnbo]

Part 6 of 8. Base: #18.

What this adds

Bulk tag deletion:

kit bulk tags delete --file tags.json     # [{id}, ...]

Rename. PUT /v4/tags/{id} had no CLI command:

kit tags update <id> <name>

Remove by email:

kit tags remove-by-email <tagId> <email>

The subscribers listing now takes the filters that the API documents: --state, --created-after, --created-before, --tagged-after, and --tagged-before.

Design notes

DELETE /v4/tags/{tag_id}/subscribers identifies the subscriber with an email_address query parameter. This is why del() needed query support in part 1. The request carries no body. A test asserts both facts.

The spec parameter list for that endpoint does not declare email_address. The endpoint description does, and it names the parameter explicitly. This branch follows the description.

Review notes

Tests: 306 before, 334 after.

Closes #10
Part of #12

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The stack

Merge from the top down. Each part builds on the one above it.

	PR	Contents
1	#14	Client query support and shared helpers
2	#15	Sequence CRUD and sequence emails
3	#16	Posts and snippets
4	#17	Broadcast filters, account-wide stats, link clicks
5	#18	Subscriber slim listing, warnings, filter
6	#19 (this one)	Tag rename, remove-by-email, bulk delete
7	#20	Account endpoints and purchase create
8	#21	Spec coverage map and its tests

Base branch: main for part 1, the previous part's branch for the rest.
GitHub retargets each base to main as the part below it merges.