feat: add get space tool

[Tom8810]

Why

The kintone MCP had no dedicated way to read space metadata and portal settings via the Space REST API (GET /k/v1/space.json). This makes it harder to inspect space name, default thread, visibility, HTML body, cover image, widget visibility, member count, attached apps, and who may create apps (EVERYONE vs ADMIN) without mutating anything.

For the same reasons as other Space-related operations, this tool is disabled when using API token authentication (consistent with kintone-get-apps and kintone-add-app).

What

• Add kintone-get-space: input is the space ID (numeric string). Calls KintoneRestAPIClient.space.getSpace and returns both structured content and pretty-printed JSON text.
• Add spaceSchema (Zod) so inputs/outputs and field descriptions are explicit.
• Add unit tests for tool name, description, input/output schemas, and the mocked callback path.
• Update manifest.json, README.md, and README_en.md, and extend tool-filters so the tool is excluded under API token auth.
• Extend test createMockClient with a space.getSpace mock hook.

How to test

1. Configure a kintone environment where you can view a space, with KINTONE_BASE_URL and credentials that the Space API accepts (not API-token-only if you expect this tool to be available).
2. With API token only, confirm kintone-get-space is not enabled (or does not appear in the tool list), matching other excluded tools.
3. With username/password (or other supported user auth), call kintone-get-space with a valid space id.
4. Verify the response includes expected fields such as name, defaultThread, isPrivate, body, attachedApps, and permissions.createApp.
5. Optionally cross-check values against the space in the kintone administration UI.

Checklist

• Updated documentation if it is required.
• Added tests if it is required.
• Passed pnpm lint and pnpm test on the root directory.