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.

terraform/main.tf

@@ -0,0 +1,68 @@
+resource "incus_project" "agathos" {
+  name        = var.project_name
+  description = "Agathos Project"
+  remote      = "local"
+  config = {
+    "features.storage.volumes" = true
+    "features.images"          = true
+    "features.profiles"        = true
+    "features.storage.buckets" = true
+    "features.networks"        = false
+  }
+}
+
+resource "incus_profile" "sandbox" {
+  name        = var.profile_name
+  project     = var.project_name
+  description = "Sandbox profile for Uranian hosts"
+  remote      = "local"
+  config = {
+    "limits.memory" = "25GB"
+    "limits.cpu"    = "13"
+  }
+
+  device {
+    name = "eth0"
+    type = "nic"
+    properties = {
+      nictype = "bridged"
+      parent  = var.network_name
+    }
+  }
+  
+  device {
+    type = "disk"
+    name = "root"
+    properties = {
+      pool = "default"
+      path = "/"
+    }
+  }
+}
+
+resource "incus_image" "noble" {
+  project = var.project_name
+
+  source_image = {
+    remote = "images"
+    name   = "ubuntu/noble/cloud"
+  }
+}
+
+resource "incus_image" "plucky" {
+  project = var.project_name
+
+  source_image = {
+    remote = "images"
+    name   = "ubuntu/plucky/cloud"
+  }
+}
+
+resource "incus_image" "questing" {
+  project = var.project_name
+
+  source_image = {
+    remote = "images"
+    name   = "ubuntu/questing/cloud"
+  }
+}