docs: add ermnvldmr platform architecture and operations guide (en/ru), remove deprecated root section (#43)

### Summary of Changes

- **Added `ermnvldmr` Platform Documentation (English & Russian)**:
  - `_index.md`: Overview and navigation cards
- `architecture.md`: End-to-end architecture (Packer, Cloud-Init, K3s,
Flux v2, Cloudflare) with Mermaid diagram
- `golden-image.md`: Packer QEMU build pipeline, S3 storage & quota
pruning
- `deployment-gitops.md`: Declarative Flux GitOps, release pipelines,
fast-track deploys, and automated `/version.json` rollout validation
- `operations.md`: SSH access, SOPS + Age secret encryption, PostgreSQL
storage, S3 backups, and Cloudflare configuration
- **Deprecated Section Cleanup**:
- Deleted obsolete `services/docs/content/en/root/` and
`services/docs/content/ru/root/`

services/docs/content/en/_index.md

@@ -7,7 +7,7 @@ title: "Ermnvldmr's Documentation"
 Welcome to the unified documentation for my own projects
 
 {{< cards >}}
+{{< card link="ermnvldmr" title="ermnvldmr.com Platform" icon="cloud" subtitle="Cloud-native infrastructure, Packer golden image, K3s cluster, and GitOps platform" >}}
 {{< card link="apex" title="apex.ermnvldmr.com" icon="server" subtitle="Fleet operations framework: a stdlib-python engine and a shared compose core" >}}
 {{< card link="quetza" title="Quetza Bot" icon="terminal" subtitle="Modular Discord bot framework documentation" >}}
-{{< card link="root" title="ermnvldmr.com-root-commons (deprecated)" icon="archive" subtitle="Deprecated — superseded by the apex framework" >}}
 {{< /cards >}}