feat(numbers): add number sequences store; restrict companysetting keys

- Add `numbers` store module with `list` and `update` methods backed by
  the `numbers` table (prefix, padding, next) per company.
- Add sql queries LIST_BY_COMPANY, GET_BY_COMPANY_AND_ID, UPDATE_...
- Regenerate and wire API docs for `numbers`.

companysetting:
- Remove the `delete` endpoint (settings are now upsert/read only).
- Restrict `set` to a fixed allow-list of keys:
  ui.theme, keys.tavily, keys.openrouter, labelprinter.addr, labelprinter.type.
- Drop DELETE_BY_COMPANY_AND_KEY sql and the delete store file.

Docs: update README, API.md, API.companysetting.md, API.numbers.md.

API.numbers.md

@@ -0,0 +1,58 @@
+# numbers
+
+This document is auto-generated from the JSDoc comments in `src/store` by running `npm run api-doc`.
+
+## `numbers.list`
+
+*Source: `src/store/numbers/list.js`*
+
+Lists the number sequences of the user's selected company.
+
+**Parameters**
+
+| Name | Type | Description |
+| --- | --- | --- |
+| `googleAuthId` | `number` | The id of the Google auth user. |
+
+**Returns**
+
+`Promise<Array<{id: number, type: string, prefix: string, padding: number, next: number}>>` — The number sequences.
+
+**Example**
+
+```js
+const numbers = await store.numbers.list(42);
+// => [{ id, type, prefix, padding, next }]
+```
+
+## `numbers.update`
+
+*Source: `src/store/numbers/update.js`*
+
+Updates the sequence settings of a number for the user's selected company. Only the provided fields are changed (all optional). `prefix` is trimmed and must be at most 50 characters. `padding` and `next` must be finite numbers greater than or equal to 0 and 1 respectively. If no field is provided, the row is returned unchanged.
+
+**Parameters**
+
+| Name | Type | Description |
+| --- | --- | --- |
+| `googleAuthId` | `number` | The id of the Google auth user. |
+| `id` | `number` | The id of the number sequence to update. |
+| `input` | `object` | The update input. |
+| `[input.prefix]` | `string` | The new prefix. |
+| `[input.padding]` | `number` | The new padding length. |
+| `[input.next]` | `number` | The new next value. |
+
+**Returns**
+
+`Promise<{id: number, type: string, prefix: string, padding: number, next: number}>` — The updated number sequence.
+
+**Throws**
+
+`Error` — If the number is not found or a field is invalid.
+
+**Example**
+
+```js
+const number = await store.numbers.update(42, 3, { prefix: 'A-', padding: 4, next: 100 });
+// => { id, type, prefix, padding, next }
+```