[fty4]

Part of #52 (work package 5: content restructure). Closes nothing; #52 stays open for work packages 8 and 9 and the docs snapshot step.

What changes

docs/ is reorganised into five sections, each with an intro page and a _category_.json:

Section	For	Pages
Write	document authors, non-technical	Download a PDF, Fill in the document, Images and logos, When something goes wrong (error catalogue), Limits you may hit
Configure	Collection admins	Choose a Template and Configuration
Deploy	operators	Prerequisites first (own Outline only; the injector is required, with the edge -> injector -> Outline picture), Docker Compose, Injector, Image fetching, Limits, Security notes, Upgrading; coming soon: Helm/Kubernetes (#51), reverse-proxy recipes, Podman
Templates	template authors	Author guide, Packages, Standard Fields, Metadata reference, and a generated Catalogue (neutral)
Internals	the curious	Architecture, Worker pipeline, Images, Security, Development, ADRs

• Home page: designed landing in website/src/pages/index.js (numbered list of the five sections, one line each), five sections in the navbar. docs/README.md stays a plain table for GitHub and is excluded from the site.
• Error catalogue: 46 codes, one permanent ### \code` anchor each (#no_binding, #busy, #user_limit, ...). scripts/docs-error-codes.sh check` compares the codes in the source with the entries on the page (46 and 46).
• Template catalogue: scripts/docs-catalogue/ (Go, reuses the product's package loader and metadata resolver, so every block shown passed the real checks) generates the pages from the template packages. Tasks docs:catalogue, docs:catalogue-check, docs:catalogue-preview, docs:errors-check. The preview image docs/assets/screens/template-neutral.png is rendered with the real pipeline and committed.
• The Outline UI screenshots from feat: generate documentation screenshots from the dev stack #66 are used on the Write pages.
• Stale paths updated: README, THIRD_PARTY_NOTICES, code comments and tests that named moved pages (only references to docs paths were touched outside docs/).

Not done

• CI does not yet run docs:catalogue-check and docs:errors-check. Adding them is a workflow change (work package 8).
• package-lock.json in the repo root still has the name outline-latex-pdf (from the logo kit); not part of this PR.
• The Write pages name a few internal phase names (gateway, worker, tex) where the real error messages contain them.

Test plan

• strict site build passes; images under the excluded assets/** are bundled
• none of 2095 links in the built HTML has link text ending in .md
• error codes: 46 in the source, 46 on the page
• docs:catalogue-check clean; the metadata blocks on the Write pages pass the real resolver
• task sanitize, task test, task test-guard
• served locally: home, the five sections, catalogue, /adr/, a coming-soon page and the error anchors return 200; light and dark screenshots checked
• CI