Add addEventListener/removeEventListener with DOM-model on* semantics (#573)

* feat(events): DOM-model on* semantics with addEventListener/removeEventListener

Fixes #551 (useHostStyles broken: fonts clobber theme/CSS variables)
Fixes #225 (user onhostcontextchanged and SDK hooks mutually exclusive)

The on* setters now follow the DOM event model:
- Replace semantics (like el.onclick) with getters
- Coexist with addEventListener/removeEventListener listeners
- Both channels fire on dispatch: on* handler then listeners

Introduces ProtocolWithEvents base class between Protocol and
App/AppBridge. Each notification event gets a slot with two independent
channels (singular on* handler + addEventListener listener array).

useHostStyles hooks now use addEventListener with proper cleanup,
so they compose correctly with user on* handlers.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Fix typedoc validation warnings

- Export AppEventMap, AppBridgeEventMap, ProtocolWithEvents so they
  appear in generated docs (they're part of public addEventListener
  signatures)
- Move AppBridgeEventMap above the AppBridge class JSDoc — it had been
  inserted between the doc block and the class, orphaning the AppBridge
  docs onto the wrong type
- Drop @param callback tags from on* getter/setter pairs — typedoc
  attaches the doc block to the getter signature which has no params
- Add MethodSchema to intentionallyNotExported (internal zod helper
  referenced by the now-documented eventSchemas field)

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

typedoc.config.mjs

@@ -28,7 +28,7 @@ const config = {
   ],
   excludePrivate: true,
   excludeInternal: false,
-  intentionallyNotExported: ["AppOptions"],
+  intentionallyNotExported: ["AppOptions", "MethodSchema"],
   blockTags: [...OptionDefaults.blockTags, "@description"],
   jsDocCompatibility: {
     exampleTag: false,