refactor: replace array-based expressions with typed class hierarchy

Replace the old Lisp-like array expression representation
(["AND", ["PARAM", ...], ...]) with a class hierarchy rooted in
an abstract Expression class (Literal, Parameter, Binary, Unary,
FunctionCall, Conditional). This gives compile-time type safety
to expression construction, evaluation, and pattern matching.

Key changes:
- New lib/common/expression.ts defines the class hierarchy with
  map/evaluate/toString methods
- Rewrite parser as hand-rolled recursive descent, removing the
  parsimmon dependency
- Extend Path with a colon separator to unify parameter identity
  and attributes into a single address space (e.g.
  "Device.WiFi.SSID.1.Name:writable"). The colon field tracks
  how many trailing segments are attribute qualifiers. PathSet
  rewritten with separate param/attr segment indexes
- Flatten device attribute representation in the UI to
  colon-delimited keys mirroring the new path syntax

ui/components/device-actions.ts

@@ -19,7 +19,7 @@ const component: ClosureComponent = (): Component => {
             onclick: () => {
               taskQueue.queueTask({
                 name: "reboot",
-                device: device["DeviceID.ID"].value[0],
+                device: device["DeviceID.ID"],
               });
             },
           },
@@ -35,7 +35,7 @@ const component: ClosureComponent = (): Component => {
             onclick: () => {
               taskQueue.queueTask({
                 name: "factoryReset",
-                device: device["DeviceID.ID"].value[0],
+                device: device["DeviceID.ID"],
               });
             },
           },
@@ -51,7 +51,7 @@ const component: ClosureComponent = (): Component => {
             onclick: () => {
               taskQueue.stageDownload({
                 name: "download",
-                devices: [device["DeviceID.ID"].value[0]],
+                devices: [device["DeviceID.ID"]],
               });
             },
           },
@@ -66,7 +66,7 @@ const component: ClosureComponent = (): Component => {
             title: "Delete device",
             onclick: () => {
               if (!confirm("Deleting this device. Are you sure?")) return;
-              const deviceId = device["DeviceID.ID"].value[0];
+              const deviceId = device["DeviceID.ID"];
 
               store
                 .deleteResource("devices", deviceId)