docs: archive repository with standardized deprecation notice

- Replace README.md with comprehensive archival template
- Add clear warning that this is historical reference only
- Redirect users to production Torrust Tracker Deployer
- Explain 3-repository PoC series evolution
- Provide migration path with actionable steps
- Preserve all historical documentation for reference
- Fix markdown linting issues (MD013 line-length violations)

This repository is now properly prepared for archival as part of the
broader project consolidation moving to the Rust-based production
Torrust Tracker Deployer system.

Author: josecelano

README.md

@@ -1,28 +1,67 @@
 [![Testing](https://github.com/torrust/torrust-tracker-deploy-bash-poc/actions/workflows/testing.yml/badge.svg)](https://github.com/torrust/torrust-tracker-deploy-bash-poc/actions/workflows/testing.yml)
 
-# Torrust Tracker Deploy (Frozen Proof of Concept)
+# Torrust Tracker Deploy - Bash PoC (Historical)
 
-> ⚠️ REPOSITORY STATUS: **This repository is now FROZEN as a historical Proof of Concept (PoC).**
+> ⚠️ **PROOF OF CONCEPT - HISTORICAL REFERENCE ONLY**
 >
-> - No new features or major refactors will be implemented here.
-> - Active engineering has moved to a **greenfield redesign initiative** documented under
->   `docs/redesign/` ([Issue #31](https://github.com/torrust/torrust-tracker-deploy-bash-poc/issues/31)).
-> - Only documentation, requirements, and architecture specification updates are accepted in
->   this repo.
+> This repository contains the first proof of concept for Torrust Tracker deployment infrastructure.
+> It is **no longer actively developed** and exists only as a historical reference.
 >
-> If you are evaluating how Torrust Tracker _will_ be deployed going forward, start with: `docs/redesign/README.md`.
+> **👉 For production use, see [Torrust Tracker Deployer](https://github.com/torrust/torrust-tracker-deployer)**
+>
+> ---
+
+## Purpose
+
+This was the first proof of concept in a series exploring deployment automation for the Torrust Tracker:
+
+1. **[Bash/OpenTofu/cloud-init PoC](https://github.com/torrust/torrust-tracker-deploy-bash-poc)**
+   (this repository)
+
+   - **Technologies**: Bash scripts, OpenTofu, cloud-init, Docker Compose
+   - **Focus**: Infrastructure as Code with libvirt/KVM and cloud deployment
+   - **Status**: ✅ Historical reference - Completed its research goals
+
+2. **[Perl/Ansible PoC](https://github.com/torrust/torrust-tracker-deploy-perl-poc)**
+
+   - **Technologies**: Perl, OpenTofu, Ansible, libvirt/KVM, cloud-init, Docker Compose
+   - **Focus**: Declarative configuration management with mature automation tools
+   - **Status**: ✅ Historical reference - Completed its research goals
+
+3. **[Torrust Tracker Deployer](https://github.com/torrust/torrust-tracker-deployer)** (production)
+   - **Technologies**: Rust, OpenTofu, Ansible, LXD, cloud-init, Docker Compose
+   - **Focus**: Type-safe, performance-oriented deployment tooling
+   - **Status**: 🚀 Production-ready - Active development
+
+## What We Learned
+
+This proof of concept successfully validated:
+
+- ✅ Infrastructure as Code approach with OpenTofu/Terraform
+- ✅ cloud-init for VM initialization
+- ✅ libvirt/KVM for local testing
+- ✅ Docker Compose for application orchestration
+- ✅ Bash scripting feasibility for deployment automation
+
+These learnings informed the design of the production Torrust Tracker Deployer.
+
+## Migration Path
+
+If you're using this PoC, migrate to the production [Torrust Tracker Deployer](https://github.com/torrust/torrust-tracker-deployer):
+
+1. Review the [Torrust Tracker Deployer README](https://github.com/torrust/torrust-tracker-deployer#readme)
+2. Check the [migration guide](https://github.com/torrust/torrust-tracker-deployer/docs/migration-from-pocs.md)
+   (if available)
+3. Open an [issue](https://github.com/torrust/torrust-tracker-deployer/issues) if you need assistance
 
-This PoC still demonstrates a full twelve-factor style deployment (infrastructure provisioning +
-application lifecycle) and remains a reference for baseline behaviors. Its documentation is
-being actively curated to extract reusable requirements for the next-generation implementation.
+---
 
-Historic description (legacy context retained below for reference):
+## Historical Documentation (Reference)
 
 This repo contains all the configuration needed to run the live Torrust Tracker Deploy.
 
-> (Legacy notice) We were in the process of
-> [splitting the Torrust Demo repo into two repos](https://github.com/torrust/torrust-demo/issues/79).
-> That plan has been superseded by the broader redesign captured in Issue #31.
+> **Note**: The original plan to split the Torrust Demo repo into two repos was superseded
+> by the broader redesign captured in the production Torrust Tracker Deployer.
 
 ## 🏗️ Repository Structure