feat: vollst. Installations-Doku, Ansible-Rollen ausimplementiert, claude_workspace-Rolle

- docs/installation.md: Netinstall + Dualboot Schritt-für-Schritt (LUKS nur am Notebook)
- docs/postinstall-ansible.md: Ablauf + restmanuelle Schritte
- roles/base: APT-Sources mit non-free-firmware + Backports, Locale, Tastatur, Zeitzone, Grundpakete
- roles/desktop_kde: Plasma 6 + SDDM (ohne Recommends, kompakt)
- roles/hardening: SSH key-only, UFW, unattended-upgrades
- roles/dev_tools: Node.js via NodeSource, Python, Perl, Git-Defaults
- roles/workstation_apps: Firefox, Thunderbird, LibreOffice, Codecs, KeePassXC
- roles/claude_workspace (NEU): Claude Code + ccusage, SSH-Key für Gitea, Workspace-Clone (recurse-submodules), ~/.claude/settings.json
- site.yml: alle Rollen mit Tags

ansible/roles/hardening/handlers/main.yml

@@ -0,0 +1,5 @@
+---
+- name: restart sshd
+  ansible.builtin.systemd:
+    name: ssh
+    state: restarted

ansible/roles/hardening/tasks/main.yml

@@ -1,3 +1,48 @@
 ---
-# SSH-Hardening, UFW, unattended-upgrades, fail2ban
-# TODO: implementieren — Skeleton-Datei
+- name: Security-Pakete
+  ansible.builtin.apt:
+    name:
+      - ufw
+      - unattended-upgrades
+      - apt-listchanges
+    state: present
+
+- name: SSH — Passwort-Login deaktivieren
+  ansible.builtin.lineinfile:
+    path: /etc/ssh/sshd_config
+    regexp: '^#?\s*PasswordAuthentication\s'
+    line: 'PasswordAuthentication no'
+    validate: 'sshd -t -f %s'
+  notify: restart sshd
+
+- name: SSH — Root-Login deaktivieren
+  ansible.builtin.lineinfile:
+    path: /etc/ssh/sshd_config
+    regexp: '^#?\s*PermitRootLogin\s'
+    line: 'PermitRootLogin no'
+    validate: 'sshd -t -f %s'
+  notify: restart sshd
+
+- name: UFW Default Policy (incoming deny)
+  ansible.builtin.command: ufw default deny incoming
+  register: ufw_default
+  changed_when: "'Default incoming policy changed' in ufw_default.stdout"
+
+- name: UFW — SSH erlauben
+  ansible.builtin.command: ufw allow OpenSSH
+  register: ufw_allow
+  changed_when: "'Rule added' in ufw_allow.stdout or 'Rules updated' in ufw_allow.stdout"
+
+- name: UFW aktivieren
+  ansible.builtin.command: ufw --force enable
+  register: ufw_enable
+  changed_when: "'Firewall is active' in ufw_enable.stdout"
+
+- name: unattended-upgrades konfigurieren
+  ansible.builtin.copy:
+    dest: /etc/apt/apt.conf.d/20auto-upgrades
+    mode: '0644'
+    content: |
+      APT::Periodic::Update-Package-Lists "1";
+      APT::Periodic::Unattended-Upgrade "1";
+      APT::Periodic::AutocleanInterval "7";