feat: add update_book and update_chapter tools

[strausmann]

Summary

Books and chapters could be created and deleted, but not renamed or moved,
via the MCP layer — the only way to rename one was to drop to the raw
BookStack REST API. update_chapter closes most of the gap tracked in #12
(thanks @scocchiarella for the API research there — the field list below
matches your proposal).

• update_book(id, {name?, description?, tags?})
• update_chapter(id, {name?, description?, book_id?, priority?, tags?})
  — book_id moves the chapter to another book, priority reorders it
  within its book.

Scope notes:

• Not included: Feature: update_chapter tool and priority support for content ordering #12 also proposed adding priority to update_page. Left
  out to keep this focused — happy to follow up.
• update_book intentionally exposes only name/description/tags,
  matching update_shelf's scope. image_id (multipart upload, not a
  JSON PUT field) and default_template_id were left out deliberately;
  easy to add later if wanted.
• Both mirror the existing update_page/update_shelf pattern exactly:
  same write-gate guard, same enhance*Response wrapping, same Zod schema
  style. No new patterns, no new permission logic.

Testing

type-check / build / test all pass unchanged (the existing 4-test
suite covers only the concurrency limiter).

Heads-up on the test setup — I did NOT use a throwaway instance as
CONTRIBUTING.md recommends. I verified end-to-end against an existing,
live BookStack instance with the built server (BOOKSTACK_ENABLE_WRITE=true):
renamed a book, renamed + reordered a chapter, and moved a chapter to a
different book — all via the new tools, independently confirmed via a
second untouched MCP session against the same instance. All test objects
were clearly marked (PRTEST-…), created and then permanently deleted as
part of the run; recycle bin verified empty afterward. Nothing left behind.

No new automated tests were added: the project has no coverage of actual
BookStack API calls anywhere (per CONTRIBUTING.md), and introducing an
API-mocking harness felt like a separate decision for you rather than
something to bundle here. Not re-tested explicitly: the ENABLE_WRITE=false
path and invalid-id / non-existent-target-book error paths — both go
through the exact same shared code as update_page/update_shelf.

Version

Left package.json untouched — say the word for a bump (5.3.0 → 5.4.0)
since that triggers your tag/release flow.

[Copilot]

Pull request overview

Adds missing BookStack “update” capabilities for books and chapters to the MCP server’s write-tool surface area, aligning these operations with existing update_page / update_shelf patterns so users can rename/move/reorder without dropping to raw REST calls.

Changes:

• Register new write tools: update_book and update_chapter (with book_id move + priority reorder support).
• Implement corresponding BookStackClient methods: updateBook() and updateChapter() using PUT endpoints.
• Update README feature/tool listing to reflect the added tools and updated write-tool count.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/index.ts	Registers update_book and update_chapter write tools with Zod input schemas and tool handlers.
src/bookstack-client.ts	Adds updateBook and updateChapter client methods that call BookStack PUT endpoints and return enhanced responses.
README.md	Updates tool counts and write-tool table to include the new update tools.

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[strausmann]

Addressed the Copilot note on priority: it now validates as a non-negative integer at the tool boundary (z.coerce.number().int().min(0)), so floats and negatives are rejected up front rather than surfacing as a BookStack error or unexpected ordering (fa51cb9). type-check/build/tests still pass unchanged.

[ttpears]

build is green, and a trial merge onto main passes type-check/build/test locally (9/9).

docker-preview failing is not this PR — fork PRs get a read-only GITHUB_TOKEN, so the GHCR push returns denied: installation not allowed to Write organization package. Only build is required. Gating that job on same-repo PRs is a separate fix.

Test setup is fine as described — a PUT passthrough doesn't need a throwaway instance.

re: version — leave package.json alone, I'll cut the release.

update_page priority from #12 stays open as the follow-up.