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/oauth2_proxy/docker-compose.yml.j2

@@ -0,0 +1,29 @@
+---
+# OAuth2-Proxy Docker Compose Configuration
+# Provides OIDC authentication for protected services
+# Red Panda Approved
+
+services:
+  oauth2-proxy:
+    image: quay.io/oauth2-proxy/oauth2-proxy:v7.6.0
+    container_name: oauth2-proxy
+    user: "{{ oauth2_proxy_uid }}:{{ oauth2_proxy_gid }}"
+    ports:
+      - "{{ oauth2_proxy_port }}:4180"
+    volumes:
+      - ./oauth2-proxy.cfg:/etc/oauth2-proxy/oauth2-proxy.cfg:ro
+    command:
+      - --config=/etc/oauth2-proxy/oauth2-proxy.cfg
+    restart: unless-stopped
+    logging:
+      driver: syslog
+      options:
+        syslog-address: "tcp://127.0.0.1:{{ oauth2_proxy_syslog_port }}"
+        syslog-format: "{{ syslog_format }}"
+        tag: "oauth2-proxy"
+    healthcheck:
+      test: ["CMD", "wget", "--quiet", "--tries=1", "--spider", "http://localhost:4180/ping"]
+      interval: 30s
+      timeout: 10s
+      retries: 3
+      start_period: 10s