Add authentication: admin/agent bearer tokens for the API, login for the dashboard

control-api: every route now carries a mandatory access level (admin / agent /
open) in a route table. All /api/v1/admin/* require the admin token; the
write calls of validator-agent and prober (self-check, events, results,
complete) require a separate static agent token; register, heartbeat and
fetching the assignment stay open. Tokens come from env vars, are compared in
constant time and never logged. An empty token leaves that level open with a
startup warning (backward compatible).

validator-agent / prober: apiclient sends the agent token only to control-api.

admin-dashboard: login/password (from env) with a stateless HMAC session
cookie, Origin-based CSRF check, per-IP brute-force throttle, HX-Redirect for
htmx polls, logout in the sidebar; the dashboard calls control-api with the
admin token. Login page layout fixed after review.

Also: env plumbing in docker-compose/rxprod-compose/systemd/config examples,
e2e script with token assertions, tests, docs (API, SETUP, USAGE, DASHBOARD,
README), plan and review under docs/changes/, bin/ rebuilt with new
SHA256SUMS.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

deploy/systemd/admin-dashboard.service

@@ -8,6 +8,11 @@ Type=simple
 User=cloud-ip-validator
 Group=cloud-ip-validator
 ExecStart=/usr/local/bin/admin-dashboard -config /etc/cloud-ip-validator/admin-dashboard.yaml
+# Optional (leading "-": the file may be absent). Holds
+# ADMIN_DASHBOARD_CONTROL_API_TOKEN (control-api's admin token) and the
+# dashboard login: ADMIN_DASHBOARD_USERNAME, ADMIN_DASHBOARD_PASSWORD,
+# ADMIN_DASHBOARD_SESSION_SECRET. Keep it mode 0600, owned by the service user.
+EnvironmentFile=-/etc/cloud-ip-validator/admin-dashboard.env
 Restart=on-failure
 RestartSec=5
 NoNewPrivileges=true

deploy/systemd/control-api.service

@@ -13,7 +13,9 @@ ExecStart=/usr/local/bin/control-api -config /etc/cloud-ip-validator/control-api
 # (auth_method: token) or OS_USERNAME / OS_USER_DOMAIN_NAME / OS_PASSWORD
 # (auth_method: password) — see docs/SETUP.md. Keep this file mode 0600,
 # owned by the service user; never commit it or put credentials in the
-# YAML config.
+# YAML config. Also holds CONTROL_API_ADMIN_TOKEN and CONTROL_API_AGENT_TOKEN
+# (generate each with `openssl rand -hex 32`); when unset, the matching API
+# level stays open and control-api logs a warning.
 EnvironmentFile=/etc/cloud-ip-validator/control-api.env
 WorkingDirectory=/var/lib/cloud-ip-validator
 Restart=on-failure

deploy/systemd/prober.service

@@ -8,6 +8,10 @@ Type=simple
 User=cloud-ip-validator
 Group=cloud-ip-validator
 ExecStart=/usr/local/bin/prober -config /etc/cloud-ip-validator/prober.yaml
+# Optional (leading "-": the file may be absent). Holds CONTROL_API_AGENT_TOKEN,
+# the same value as on control-api. Keep it mode 0600, owned by the service
+# user.
+EnvironmentFile=-/etc/cloud-ip-validator/prober.env
 Restart=on-failure
 RestartSec=5
 NoNewPrivileges=true

deploy/systemd/validator-agent.service

@@ -8,6 +8,10 @@ Type=simple
 User=cloud-ip-validator
 Group=cloud-ip-validator
 ExecStart=/usr/local/bin/validator-agent -config /etc/cloud-ip-validator/validator-agent.yaml
+# Optional (leading "-": the file may be absent). Holds CONTROL_API_AGENT_TOKEN,
+# the same value as on control-api. Keep it mode 0600, owned by the service
+# user.
+EnvironmentFile=-/etc/cloud-ip-validator/validator-agent.env
 Restart=on-failure
 RestartSec=5
 NoNewPrivileges=true