feat(iac): establish Ansible baseline for Nginx, SearXNG, Valkey, and Certbot

- Reverse-engineer live Debian 13 (trixie) VPS state at miguelpedro.xyz.br
- Add modular Ansible roles: common, certbot, valkey, searxng, and nginx
- Encrypt SearXNG secret_key using ansible-vault in group_vars/all/vault.yml
- Cleanly remove unused example.com Nginx stub symlink (sites-enabled/miguelpedro.xyz.br)
- Scaffold cgit + fcgiwrap role (cgit_enabled: false) for upcoming deployment
- Add DISCOVERY_REPORT.md, COMMAND_LOG.md, README.md, and AGENT_INSTRUCTIONS.md with Self-Updating Protocol

1 files changed, 49 insertions, 0 deletions

diff --git a/roles/searxng/templates/limiter.toml.j2 b/roles/searxng/templates/limiter.toml.j2
new file mode 100644
index 0000000..0b40bf8
--- /dev/null
+++ b/roles/searxng/templates/limiter.toml.j2
@@ -0,0 +1,49 @@
+[botdetection]
+
+# The prefix defines the number of leading bits in an address that are compared
+# to determine whether or not an address is part of a (client) network.
+
+ipv4_prefix = 32
+ipv6_prefix = 48
+
+# If the request IP is in trusted_proxies list, the client IP address is
+# extracted from the X-Forwarded-For and X-Real-IP headers. This should be
+# used if SearXNG is behind a reverse proxy or load balancer.
+
+trusted_proxies = [
+  '127.0.0.0/8',
+  '::1',
+  # '192.168.0.0/16',
+  # '172.16.0.0/12',
+  # '10.0.0.0/8',
+  # 'fd00::/8',
+]
+
+[botdetection.ip_limit]
+
+# To get unlimited access in a local network, by default link-local addresses
+# (networks) are not monitored by the ip_limit
+filter_link_local = false
+
+# activate link_token method in the ip_limit method
+link_token = false
+
+[botdetection.ip_lists]
+
+# In the limiter, the ip_lists method has priority over all other methods -> if
+# an IP is in the pass_ip list, it has unrestricted access and it is also not
+# checked if e.g. the "user agent" suggests a bot (e.g. curl).
+
+block_ip = [
+  # '93.184.216.34',  # IPv4 of example.org
+  # '257.1.1.1',      # invalid IP --> will be ignored, logged in ERROR class
+]
+
+pass_ip = [
+  # '192.168.0.0/16',      # IPv4 private network
+  # 'fe80::/10'            # IPv6 linklocal / wins over botdetection.ip_limit.filter_link_local
+]
+
+# Activate passlist of (hardcoded) IPs from the SearXNG organization,
+# e.g. `check.searx.space`.
+pass_searxng_org = true