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/pgadmin/deploy.yml

@@ -0,0 +1,61 @@
+---
+- name: Deploy PgAdmin
+  hosts: ubuntu
+  tasks:
+  - name: Check if host has pgadmin service
+    ansible.builtin.set_fact:
+      has_pgadmin_service: "{{'pgadmin' in services}}"
+
+  - name: Skip hosts without pgadmin service
+    ansible.builtin.meta: end_host
+    when: not has_pgadmin_service
+
+  - name: Add PgAdmin repository
+    become: true
+    ansible.builtin.deb822_repository:
+      name: pgadmin4
+      types: [deb]
+      uris: https://ftp.postgresql.org/pub/pgadmin/pgadmin4/apt/{{ansible_distribution_release}}
+      suites: [pgadmin4]
+      components: [main]
+      signed_by: https://www.pgadmin.org/static/packages_pgadmin_org.pub
+      state: present
+
+  - name: Install PgAdmin
+    become: true
+    ansible.builtin.apt:
+      name: pgadmin4-web
+      state: present
+      update_cache: true
+
+  # -------------------------------------------------------------------------
+  # SSL Certificate Distribution for External PostgreSQL Connections
+  # -------------------------------------------------------------------------
+
+  - name: Create PGadmin certs directory
+    become: true
+    ansible.builtin.file:
+      path: /var/lib/pgadmin/certs
+      state: directory
+      owner: www-data
+      group: www-data
+      mode: '0750'
+
+  - name: Fetch Titania PostgreSQL SSL cert
+    become: true
+    ansible.builtin.fetch:
+      src: /etc/postgresql/17/main/ssl/server.crt
+      dest: /tmp/titania-postgres-ca.crt
+      flat: yes
+    delegate_to: titania.incus
+    when: "'titania.incus' in groups['ubuntu']"
+
+  - name: Copy Titania PostgreSQL SSL cert to PGadmin
+    become: true
+    ansible.builtin.copy:
+      src: /tmp/titania-postgres-ca.crt
+      dest: /var/lib/pgadmin/certs/titania-postgres-ca.crt
+      owner: www-data
+      group: www-data
+      mode: '0644'
+    when: "'titania.incus' in groups['ubuntu']"