feat: smart zomboid traffic filtering with packet-size detection

Replace per-IP hashlimit with smarter filtering that distinguishes
legitimate players from scanner bots based on packet behavior:
- Players send varied packet sizes (53, 37, 1472 bytes)
- Scanners only send 53-byte query packets

New firewall rule chain:
- Priority 2: Mark + ACCEPT non-query packets (verifies player)
- Priority 3: ACCEPT queries from verified IPs (1 hour TTL)
- Priority 4: LOG rate-limited queries from unverified IPs
- Priority 5: DROP rate-limited queries (2 burst, then 1/hour)

Also includes:
- Fail2ban zomboid jail with tighter thresholds (5 retries/4h, 1w ban)
- Graylog streams for zomboid-connections, zomboid-ratelimit, fail2ban
- GeoIP pipeline enrichment for zomboid traffic
- Fluent-bit inputs for ratelimit logs and fail2ban events
- Remove Legendary Katana mod (Workshop 3418366499) - removed from Steam
- Bump Immich to v2.5.0
- Fix fulfillr config (nil → null)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

ansible/roles/common/tasks/security.yml

@@ -21,6 +21,16 @@
   notify: restart_sshd
   tags: security
 
+- name: setup fail2ban filters
+  become: true
+  ansible.builtin.copy:
+    src: files/fail2ban/filters/{{ item }}
+    dest: /etc/fail2ban/filter.d/{{ item }}
+    mode: 0644
+  loop: "{{ fail2ban_filters }}"
+  notify: restart_fail2ban
+  tags: security
+
 - name: setup fail2ban jails
   become: true
   ansible.builtin.copy: