Zone-based firewall page, per-sensor temperatures, 15 minute default

The firewall page now manages zones (assign each LAN or tunnel, add and
remove zones) and rules with zone, address and port on both sides plus the
protocol. router.firewall.zones declares zones without members and rules
take sourcePorts. The temperature chart draws every thermal zone and hwmon
sensor; the overview defaults to 15 minutes, 1h stays an option.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AeFqV9dZrK6nipHkPfyM4F

tests/assertions.nix

@@ -310,6 +310,56 @@ let
       };
       expect = [ "ports are only valid with protocol tcp or udp" ];
     };
+    ruleSourcePortsWithoutProtocol = {
+      router = {
+        lans = {
+          main = lan { };
+          iot = lan2 { };
+        };
+        firewall.rules = [
+          {
+            from = "iot";
+            to = "main";
+            sourcePorts = [ 53 ];
+          }
+        ];
+      };
+      expect = [ "sourcePorts are only valid with protocol tcp or udp" ];
+    };
+    ruleSourcePortOutOfRange = {
+      router = {
+        lans = {
+          main = lan { };
+          iot = lan2 { };
+        };
+        firewall.rules = [
+          {
+            from = "iot";
+            to = "main";
+            protocol = "udp";
+            sourcePorts = [ "2000-1000" ];
+          }
+        ];
+      };
+      expect = [ "out of range" ];
+    };
+    ruleToDeclaredEmptyZone = {
+      router = {
+        lans.main = lan { };
+        firewall = {
+          zones = [ "guests" ];
+          rules = [
+            {
+              from = "main";
+              to = "guests";
+              protocol = "tcp";
+              sourcePorts = [ 1024 ];
+            }
+          ];
+        };
+      };
+      expect = [ ];
+    };
     ruleDestinationInvalid = {
       router = {
         lans = {