docs(environment-setup): accuracy + copy/structure (no #192 dependency)

[LukasWodka]

The #192-independent half of the Environment Setup audit, split out of #47 — correct against the current installer, safe to merge and promote now.

Accuracy

• Firewall domains (setup-guide): replaced the misleading github.com with what the installer actually hits — ghcr.io (ingestor image), raw.githubusercontent.com (install scripts), *.github.io (Helm chart repo). The old list breaks installs behind a strict firewall.
• Phantom config (configuration): removed HTTP_PORT/HTTPS_PORT — the installer disables ingress (traefik/servicelb) and binds only the API port.
• --diagnose (troubleshooting): documented the redacted support bundle (was missing).

Copy + structure

• EKS: added a "when to use EKS vs the local installer" callout + a back-link to Setup Guide (the section had no fork), plus a Quick-vs-Detailed signpost; dropped softeners ("Treat this as a solid baseline", "about 1–2 hours") and tightened verbose lines.
• Configuration: an installer-vs-manual-Helm audience signpost; tightened the GPU / "Platform behaviour" / auto-upgrade lines.

The namespace/workspace edits (which describe client#192) stay in #47, held to merge with #192.

Validated: MDX components balanced, docs.json valid. Targets develop.

[LukasWodka]

👋 Heads-up — Code review queue is at 14 / 8

Above the WIP limit. The team convention is to review existing PRs before opening new work.

Open PRs currently in Code review (oldest first):

• averaging-service#102 — chore(kanban): declare staging as prod-truth branch via .kanban.yml · author: @LukasWodka · no reviewer assigned
• averaging-service#98 — ci: add fr-gate caller workflow · author: @LukasWodka · no reviewer assigned
• client#192 — Installer UX: drop PriorityClass, fix namespace, one-per-machine guard, surface version · author: @LukasWodka · no reviewer assigned
• data-ingestors#146 — test(schema): lock category enum to the engine's TaskCategory (anti-drift) · author: @LukasWodka · reviewer: @saadqbal
• data-ingestors#148 — Develop to prod · author: @divyasinghds · reviewer: @saadqbal
• design-system#19 — fix: un-track coverage/ and node_modules/ from git · author: @LukasWodka · no reviewer assigned
• design-system#22 — ci: add Vitest test workflow · author: @LukasWodka · reviewer: @aptracebloc
• design-system#23 — ci: add fr-gate caller workflow · author: @LukasWodka · no reviewer assigned
• docs#47 — docs(environment-setup): accuracy + #192 namespace flow + copy/structure polish · author: @LukasWodka · reviewer: @saadqbal
• frontend-app#499 — ci: add Vitest + Cypress test workflow · author: @LukasWodka · reviewer: @aptracebloc

Pull from review before opening new work. (This is a nudge from the kanban WIP check, not a block.)