feat(docs): mirror hydra docs + new agents page + restructured Claude sidebar

[rubenvdlinde]

Phase 3 of the docs consolidation — re-targeted

Background. Initially attempted as hydra #273 standing up hydra.conduction.nl as its own Docusaurus site. That doesn't work — hydra is a private repo, and GitHub Pages won't serve from a private repo without Enterprise. So the work lands here instead: docs.conduction.nl already serves the public org docs, and folding hydra's docs/ tree under /hydra/ is the cleanest answer.

What this PR ships

1. docs/claude/agents.md (new)

First-class Available agents & skills page covering:

• Four pipeline personas (Al Gorithm Builder, Juan Claude van Damme Code Reviewer, Clyde Barcode Security Reviewer, Axel Plier Applier) with container, model, and turn budget — pulled from the canonical agents/<persona>/config.yaml in the hydra repo.
• The full hydra/.claude/skills/ catalogue (~50 skills) grouped: opsx-* (16 workflow), hydra-gate-* (13 quality gates), team-* (7), testing (test-* + test-persona-*), journeydoc-* (3), utilities.
• The concurrentie-analyse/.claude/skills/ catalogue (~21 skills): app-*, specter-* (research), tender-*, ecosystem-*, swc-*.
• The eight user personas from hydra/personas/.

2. docs/hydra/ mirror (18 new files)

The hydra repo's public-facing docs/ tree, mirrored here so it's served at docs.conduction.nl/hydra/. Existing docs/hydra/README.md stays as the section landing.

• Pipeline: pipeline-overview, agentic-workflow, agent-configuration, container-architecture, deployment-models, github-workflow, context
• Operations: auth, cron, dev-run, entrypoints, logging, networking, secrets, troubleshooting, README
• Retrospectives: decidesk-44-45-phase-g

⚠️ Mirror = manual sync. If hydra-side docs change, re-run the mirror. Worth automating later via a sync action (or removing docs/ from the hydra repo entirely — it's private, so nothing outside the org reads it directly anyway).

3. website/sidebars.js restructure

Replaced the flat { type: 'autogenerated', dirName: 'claude' } dump with thematic groupings:

WayOfWork/way-of-work
├── Working at Conduction
├── Building Software
├── Support & Safety
├── Hydra (NEW — collapsible category, was a single 'hydra/README' link)
│   ├── Pipeline (7 pages, collapsed)
│   ├── Operations (9 pages, auto, collapsed)
│   └── Retrospectives (1 page, auto, collapsed)
├── Using Claude (NEW — was 'Claude workflow', autogenerated flat)
│   ├── getting-started, walkthrough, agents, rad-platform   ← entry points first
│   ├── Setup (5 pages, collapsed)
│   ├── Workflow (5 pages, collapsed)
│   ├── Writing (7 pages, collapsed)
│   ├── Quality & testing (3 pages, collapsed)
│   └── retrofit
└── about-this-manual

The previous Claude workflow category dumped all 27 pages alphabetically — hard to navigate. The new structure puts entry points first and tucks deep references behind collapsed categories.

4. i18n/nl labels

Added Dutch labels for the new categories: Hydra, Pipeline, Operations, Retrospectives, Using Claude, Setup, Workflow, Writing, Quality & testing.

Test plan

• npm run build — succeeds; build/hydra/ has 9 routes plus operations + retrospectives subtrees; build/claude/agents/ exists; EN + NL builds both pass (195 files in build/nl/).
• Verified the autogenerated subtrees pick up docs/hydra/operations/ and docs/hydra/retrospectives/.
• Visual check post-merge once deploy-docs.yml rebuilds gh-pages and CDN cache clears.

Known broken-link warnings (cosmetic, pre-existing)

• Cross-repo paths in markdown (/hydra/.claude/skills/, /concurrentie-analyse/..., /.claude/memory/...) — GitHub renders them; Docusaurus doesn't. Pre-existing on main.
• One anchor warning in /claude/ for #php-quality-tools-... (link in original content, anchor isn't a heading).

What's NOT in this PR

• Mirror automation — a workflow that syncs docs/ from hydra → .github/docs/hydra/ periodically. Worth filing as a follow-up.
• Per-page Dutch markdown translations — content task.
• /privacy/ /terms/ /iso/ preset footer fix — to file on ConductionNL/design-system (where @conduction/docusaurus-preset actually lives).

Cross-repo PR chain

Repo	PR	What
.github	merged #15, #32, #9, #60	issue templates, RAD overview, docker-compose, global-settings v1.7.0
.github	merged #65	website preset ^2.6.1 + i18n/nl skeleton
.github	open #64	OpenSpec sync + issue-triage reusable workflows
hydra	closed #273	original Phase 3 — wrong target (private repo)
.github	this PR	Phase 3 re-targeted — content goes here instead