docs: fix dead chart names + modernize four platform deployment guides

[saadqbal]

The four platform-specific deployment guides under `docs/environment-setup/` all reference Helm chart names that no longer exist:

• `tracebloc/eks` (EKS guide)
• `tracebloc/aks` (Azure guide)
• `tracebloc/bm` (macOS + Linux local guides)

Per-platform charts were consolidated into the unified `tracebloc/tracebloc` chart in tracebloc/client commit `bd74124`. The `aks/`, `eks/`, and `bm/` directories are now empty. Anyone following the current docs hits a 404 at `helm install`.

Also stale across these guides:

• `azure-deployment-guide.md:1` literally says `old content` in the title.
• No mention of the unified-chart consolidation.
• No mention of the NetworkPolicy/CNI prerequisite (chart's training-pod egress lockdown silently no-ops on incompatible CNIs).
• No reference to the standalone installer (`bash <(curl -fsSL https://tracebloc.io/i.sh)\` / `irm https://tracebloc.io/i.ps1 | iex`) — recently surfaced in tracebloc/client#104.
• Self-upgrade CronJob, requests-proxy security model, `tracebloc-node-agents` namespace — none mentioned.

Acceptance criteria

• All four guides install via `tracebloc/tracebloc` (unified chart), not platform-specific names.
• All guides point at `https://tracebloc.github.io/client\` for the helm repo.
• Each guide leads with the standalone installer (`https://tracebloc.io/i.sh\` / `i.ps1` — explicit https) for users who don't have a cluster yet, then covers cluster-specific install steps.
• NetworkPolicy/CNI prerequisite called out as a callout near the top.
• `azure-deployment-guide.md` no longer labeled "old content".
• Tone pass — same voice as the recently refreshed READMEs (warm, direct, no fluff).
• Cross-link to `tracebloc/client/docs/INSTALL.md` as the canonical source-of-truth, not duplicated.

[saadqbal]

Closing as obsolete. This issue described problems in legacy Docusaurus files (docs/environment-setup/{eks-client,azure,local-deployment-{macos,linux},deployment-guide}.md) that don't exist in the active Mintlify-based repo.

The migration (commit fc61959) consolidated:

• Azure / Linux / macOS / deployment-overview → single environment-setup/setup-guide.mdx
• Old architecture → environment-setup/configuration.mdx

Plus the recent installer-URL work (commit 4221427) and Pod Security docs (commit c35a852) already addressed several of the gaps that motivated this audit.

A focused re-audit against the actual current files will be filed separately if anything substantive turns up.