fix: 674 fix dataset naming

[daveomri]

WHY

The Get Dataset Items action couldn't reference a dataset by name, silently accepted invalid limit values, showed misleading placeholder defaults, and paginated inefficiently.

Closes 674

Bug A: Dataset ID couldn't be referenced by name

The Dataset ID field was described only as "The ID of the dataset", and the dropdown passed the raw ID. The Apify API path accepts Dataset ID or username~dataset-name, but the tilde form was undocumented and unintuitive.

Now:

• Verified against the [Apify docs](https://docs.apify.com/api/v2/dataset-items-get) that the path accepts both a raw ID and username~dataset-name, and that apify-client forwards the value as-is.
• The description advertises username/dataset-name, and run() normalizes / → ~, so all three forms work: raw ID, username/dataset-name, and username~dataset-name.

Bug B: Limit accepted 0 and negatives; misleading placeholder defaults

limit had no lower bound (0 or negative silently returned nothing), and both limit (default: 100) and offset (default: 0) rendered as pre-filled values that looked intentional.

Now:

• limit has min: 1; offset has min: 0 defensively.
• Removed the defaults so both fields render empty; descriptions state that empty limit = all items and empty offset = start from the first item.

Bug C: Inefficient pagination (latent)

The fetch loop hardcoded page size to LIMIT (user's limit was a post-hoc cap), and while (total) did a gratuitous extra empty fetch before terminating.

Now:

• run() rewritten: offset empty → 0; limit set → paginate in pages of min(LIMIT, remaining) capped at the limit; limit empty → return all, terminating on a short or empty page. No post-hoc truncation, no extra empty fetch, no infinite loop.

What changed

• components/apify/apify.app.mjs: datasetId description advertises username/dataset-name; limit gets min: 1 and loses default: LIMIT; offset gets min: 0 and loses default: 0; descriptions reworded for empty = all / empty = first. (get-dataset-items is the only consumer.)
• components/apify/actions/get-dataset-items/get-dataset-items.mjs: separator normalization (/ → ~), pagination loop rewritten for optional limit/offset; 0.0.6 → 0.0.7.
• components/apify/actions/get-dataset-items/get-dataset-items.test.mjs: 12 unit tests covering pagination (limit cap, limit > dataset, empty-limit paginate-all, exact-multiple termination, empty dataset), offset passthrough and empty default, dataset ID normalization, clean/fields/omit forwarding, $summary wording, and propDef metadata.

Testing

• eslint clean.
• 12 unit tests pass (via a local jest override — the root jest.config.js is broken pre-existing).
• Verified via pd dev/pd publish against a live Apify account: username/dataset-name resolves; limit of 1 returns one item; empty limit paginates past 100 and returns all; offset skips correctly.

Before

Now