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

build/build.ts

@@ -107,13 +107,7 @@ const packageDotJsonPlugin = {
 const inlineDepsPlugin = {
   name: "inlineDeps",
   setup(build) {
-    const deps = [
-      "parsimmon",
-      "espresso-iisojs",
-      "@codemirror",
-      "mithril",
-      "yaml",
-    ];
+    const deps = ["espresso-iisojs", "@codemirror", "mithril", "yaml"];
     const depFiles = new Set();
     build.onResolve({ filter: /^[^.]/ }, async (args) => {
       if (args.pluginData === "inlineDeps") return undefined;