Per-event documentation + getPluginEvents introspection (#71)

* Add per-event documentation + getPluginEvents introspection

Mirror the per-method documentation pipeline for events. Events
(declared in a universal module's logos_events: section) now carry a
description parsed from their /// doc comments, and are introspectable
at runtime via a new getPluginEvents framework call.

- lidl_ast: EventDecl gains a description field.
- impl_header_parser: capture the event's doc comment (previously
  discarded) and an optional metadata.json events[].description.
- lidl_gen_provider: generated universal provider emits
  getEvents() override, mirroring getMethods() (name/signature/
  parameters/description; no returnType/isInvokable — events are void).
- logos_provider_object: default-empty virtual getEvents() so the
  legacy provider path and QtProviderObject inherit empty.
- module_proxy / qt_provider_object: intercept getPluginEvents next to
  the getPluginMethods special-case.
- docs: spec + README event-documentation notes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Add unit tests for event documentation + getEvents generation

Address review feedback (#71): cover the event-introspection paths that
previously only had method-side tests.

- impl_header_parser test: assert metadata.json events[].description is
  parsed; new documented_events fixture asserts `///` doc-comment
  capture on a logos_events: block (multi-line joined with \n,
  adjacent-only, plain // ignored).
- lidl_gen_provider test: assert the generated dispatch contains
  getEvents() emitting each event's name/signature/parameters and an
  escaped description, and that events carry no returnType/isInvokable.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Fold event introspection into getMethods() to keep the provider ABI stable

The previous approach added a getEvents() virtual to LogosProviderObject,
which inserted a new vtable slot and shifted every later slot — an ABI
break that would misdispatch virtual calls whenever an old and new
host/module were mixed across the in-process plugin boundary.

Instead, report events INSIDE the existing getMethods() call: it now
returns the module's whole interface, with each entry tagged
type "method" or "event" (events omit returnType/isInvokable). The
provider vtable is therefore byte-for-byte unchanged, so old/new hosts
and modules stay binary-compatible — a new host reading an old module
sees no event entries (zero events), and an old host reading a new
module just ignores the "type" field (cosmetic). An entry with no
"type" is treated as a method.

- logos_provider_object.h: remove the getEvents() virtual; document that
  getMethods() carries both, and why.
- generator (lidl_gen_provider): emit events as type "event" entries
  inside getMethods(); tag methods type "method"; no getEvents() output.
- module_proxy / qt_provider_object: getPluginMethods()/getPluginEvents()
  are now type-filtered views of getMethods(), plus a new
  getPluginInterface() returning the whole list. (These are name-
  dispatched Q_INVOKABLEs, not vtable surface — adding them is safe.)
- tests: generator asserts events fold into getMethods() tagged "event";
  ModuleProxy asserts the three filtered views; parser tests unchanged.
- docs: spec/project/docs/README updated, incl. an ABI rationale note.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

cpp-generator/experimental/impl_header_parser.cpp

@@ -233,6 +233,7 @@ ImplParseResult parseImplHeader(const QString& headerPath,
             QJsonObject evObj = ev.toObject();
             EventDecl ed;
             ed.name = evObj.value("name").toString();
+            ed.description = evObj.value("description").toString();
             QJsonArray params = evObj.value("params").toArray();
             for (const QJsonValue& pv : params) {
                 QJsonObject po = pv.toObject();
@@ -396,6 +397,7 @@ ImplParseResult parseImplHeader(const QString& headerPath,
                         EventDecl ed;
                         ed.name = md.name;
                         ed.params = md.params;
+                        ed.description = joinDocLines(pendingDoc);
                         result.module.events.append(ed);
                     }
                 }