docs: rewrite README with structured overview and quick start guide

Replaces the minimal project description with a comprehensive README
including a component overview table, quick start instructions, common
Ansible operations, and links to detailed documentation. Aligns with
Red Panda Approval™ standards.

ansible/inventory/host_vars/ariel.incus.yml

@@ -0,0 +1,24 @@
+---
+# Ariel Configuration - Graph Database Host
+# Services: alloy, docker, neo4j
+
+services:
+  - alloy
+  - docker
+  - neo4j
+
+# Alloy
+alloy_log_level: "warn"
+neo4j_syslog_port: 22011
+
+# Neo4j
+neo4j_rel: master
+neo4j_version: "5.26.0"
+neo4j_user: neo4j
+neo4j_group: neo4j
+neo4j_directory: /srv/neo4j
+neo4j_auth_user: neo4j
+neo4j_auth_password: "{{ vault_neo4j_auth_password }}"
+neo4j_http_port: 25554
+neo4j_bolt_port: 7687
+neo4j_apoc_unrestricted: "apoc.*"