feat(os): show full version number from /etc/debian_version

- Use lsb_release -is/-cs for name and codename
- Use /etc/debian_version for full version (e.g. 12.9)
- Display format: 'Debian GNU/Linux 12.9 (bookworm)'

full_updater/backend/scanner.py

@@ -137,25 +137,39 @@ def lxc_is_running(vmid: str) -> bool:
 
 
 def scan_os(target: Target) -> str:
-    """Récupère le nom et la version de l'OS."""
-    if target.is_host:
-        cmd = ["lsb_release", "-ds"]
-    else:
-        cmd = ["pct", "exec", target.target_id, "--", "lsb_release", "-ds"]
-    ok, stdout, _ = run_cmd(cmd, timeout=30)
-    if ok:
-        return stdout.strip()
-    # Fallback si lsb_release n'est pas installé
-    if target.is_host:
-        cmd = ["cat", "/etc/os-release"]
-    else:
-        cmd = ["pct", "exec", target.target_id, "--", "cat", "/etc/os-release"]
-    ok, stdout, _ = run_cmd(cmd, timeout=30)
-    if ok:
-        name = re.search(r'PRETTY_NAME="([^"]+)"', stdout)
-        if name:
-            return name.group(1)
-    return "OS inconnu"
+    """Récupère le nom, la version complète et le codename de l'OS."""
+    prefix = [] if target.is_host else ["pct", "exec", target.target_id, "--"]
+
+    # 1. Récupérer le nom (Debian, Ubuntu...)
+    ok, name_out, _ = run_cmd(prefix + ["lsb_release", "-is"], timeout=30)
+    os_name = name_out.strip() if ok else ""
+
+    # 2. Récupérer le codename (bookworm, trixie...)
+    ok, code_out, _ = run_cmd(prefix + ["lsb_release", "-cs"], timeout=30)
+    codename = code_out.strip() if ok else ""
+
+    # 3. Récupérer la version complète depuis /etc/debian_version (ex: 12.9)
+    ok, ver_out, _ = run_cmd(prefix + ["cat", "/etc/debian_version"], timeout=30)
+    version = ver_out.strip() if ok else ""
+
+    # 4. Fallback sur lsb_release -rs si /etc/debian_version vide
+    if not version:
+        ok, ver_out, _ = run_cmd(prefix + ["lsb_release", "-rs"], timeout=30)
+        version = ver_out.strip() if ok else ""
+
+    # 5. Fallback sur /etc/os-release si tout le reste échoue
+    if not os_name or not version:
+        ok, osrel_out, _ = run_cmd(prefix + ["cat", "/etc/os-release"], timeout=30)
+        if ok:
+            pretty = re.search(r'PRETTY_NAME="([^"]+)"', osrel_out)
+            if pretty:
+                return pretty.group(1)
+        return "OS inconnu"
+
+    # Construire le libellé final
+    if codename:
+        return f"{os_name} GNU/Linux {version} ({codename})"
+    return f"{os_name} GNU/Linux {version}"
 
 
 def ensure_debsecan_installed(is_host: bool, vmid: str = "") -> tuple[bool, str]: