Update documentation to reflect current architecture

## Problem

Multiple documentation files still describe the pre-July 2024 architecture (Kubernetes + Nginx) which was replaced by a Hetzner VM running Caddy.

### Specific files and references

- **`docs/infrastructure-overview.md`** (lines 45-73): Describes Nginx web server and Kubernetes Autopilot cluster as current architecture
- **`docs/deploy.md`** (lines 59-75): Contains `gcloud container clusters get-credentials` and `kubectl apply -k ../kubernetes` commands that reference a cluster that no longer exists
- **`docs/infrastructure-as-code.md`** (line 17): References a `kubernetes/` directory that doesn't exist
- **`docs/infrastructure-bootstrapping.md`** (line 3): Lists "Terraform and Kubernetes YAML" as the IaC strategy; should be Terraform + Ansible

### Additional fix

- **`.editorconfig`** (lines 11-13 and 19-21): Duplicate `[config.ru]` sections with conflicting indentation settings (space/2 vs tab/4). Remove the incorrect duplicate.

## Expected Outcome

Documentation should describe the current architecture: Hetzner VM provisioned via Ansible, Caddy as reverse proxy, Prometheus for monitoring, systemd for service management.