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/device-page.ts

@@ -1,7 +1,9 @@
-import { ClosureComponent, Component } from "mithril";
+import { ClosureComponent } from "mithril";
 import { m } from "./components.ts";
-import config from "./config.ts";
+import { device as deviceConfig } from "./config.ts";
 import * as store from "./store.ts";
+import Expression from "../lib/common/expression.ts";
+import Path from "../lib/common/path.ts";
 
 export function init(
   args: Record<string, unknown>,
@@ -14,16 +16,25 @@ export function init(
 
   return Promise.resolve({
     deviceId: args.id,
-    deviceFilter: ["=", ["PARAM", "DeviceID.ID"], args.id],
+    deviceFilter: new Expression.Binary(
+      "=",
+      new Expression.Parameter(Path.parse("DeviceID.ID")),
+      new Expression.Literal(args.id as string),
+    ),
   });
 }
 
-export const component: ClosureComponent = (): Component => {
+interface Attrs {
+  deviceId: string;
+  deviceFilter: Expression;
+}
+
+export const component: ClosureComponent<Attrs> = () => {
   return {
     view: (vnode) => {
-      document.title = `${vnode.attrs["deviceId"]} - Devices - GenieACS`;
+      document.title = `${vnode.attrs.deviceId} - Devices - GenieACS`;
 
-      const dev = store.fetch("devices", vnode.attrs["deviceFilter"]);
+      const dev = store.fetch("devices", vnode.attrs.deviceFilter);
       if (!dev.value.length) {
         if (!dev.fulfilling) {
           return m(
@@ -38,15 +49,15 @@ export const component: ClosureComponent = (): Component => {
         );
       }
 
-      const conf = config.ui.device;
+      const conf = deviceConfig;
       const cmps = [];
 
       for (const c of Object.values(conf)) {
         cmps.push(
           m.context(
             { device: dev.value[0], deviceQuery: dev },
-            store.evaluateExpression(c["type"], null) as string,
-            c,
+            store.evaluateExpression(c["type"], {}).value as string,
+            c as any,
           ),
         );
       }