Restrict the brightness sink to one app, picked by name not typed

Confirmed the brightness command applies globally, not per-LED
(serverinfo showed exactly one adjustment object, "id": "default",
covering the whole string), so no LED-count configuration is needed
for this at all -- that question resolved itself once the mechanism
was actually inspected instead of assumed.

For "only react while Spotify is running": only one app can be in the
foreground on webOS at a time, so a "capture the current app" button
in this app's own UI can never work -- pressing it means this app is
foreground, not Spotify. The only workable UI is picking a target from
every *installed* app by name, regardless of what's currently running.

That needed a new native capability this service never had: calling
OUT to another Luna service, not just being called. Two additions:

  foreground_app.c   subscribes once, at startup, to
                      com.webos.applicationManager/getForegroundAppInfo
                      and keeps a thread-safe cache the audio thread can
                      read without a blocking Luna call
  service.c           new listApps method, bridging to
                      com.webos.applicationManager/listApps so the
                      frontend never has to call another service
                      directly -- same rule as everywhere else here

Until the subscription has delivered at least one reply, a restricted
sink treats the target app as inactive, not active -- reacting to
audio when the user explicitly restricted it to one app would be the
wrong failure mode. Verified end to end on the host: engine_smoke.c
opens the sink with a restriction set, confirms it reports itself
correctly inactive against the stub Luna bus (which always "fails" to
call out, exactly like a real host with no bus).

Needed real, linkable stub bodies for LSCall/LSCallOneReply/
LSCallCancel/LSMessageGetPayload/LSErrorInit/LSErrorFree
(test/stubs/luna-service2/lunaservice_stub.c) since foreground_app.c
is the first source file here that's actually linked into a host test
binary rather than only syntax-checked -- service.c/main.c's existing
stub declarations were never called, only compiled against. Confirmed
those really are the correct symbol names by cross-compiling clean
against the real webOS SDK's actual libluna-service2, not just the
stub.

Bumped to 1.0.5.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

test/stubs/luna-service2/lunaservice.h

@@ -20,6 +20,8 @@ typedef struct {
 } LSError;
 
 typedef bool (*LSMethodFunction)(LSHandle* sh, LSMessage* msg, void* category_context);
+typedef bool (*LSFilterFunc)(LSHandle* sh, LSMessage* reply, void* ctx);
+typedef unsigned long LSMessageToken;
 
 typedef enum {
     LUNA_METHOD_FLAGS_NONE = 0,
@@ -58,6 +60,17 @@ bool LSGmainAttach(LSHandle* handle, GMainLoop* loop, LSError* error);
 const char* LSMessageGetPayload(LSMessage* message);
 bool LSMessageIsSubscription(LSMessage* message);
 bool LSMessageReply(LSHandle* sh, LSMessage* message, const char* reply, LSError* error);
+void LSMessageRef(LSMessage* message);
+void LSMessageUnref(LSMessage* message);
 
 bool LSSubscriptionAdd(LSHandle* sh, const char* key, LSMessage* message, LSError* error);
 bool LSSubscriptionReply(LSHandle* sh, const char* key, const char* payload, LSError* error);
+
+// Client-call API: this service acting as a caller of another service, not
+// just a callee. LSCall keeps calling `callback` for every reply (used for
+// subscribe:true); LSCallOneReply auto-cancels after the first one.
+bool LSCall(LSHandle* sh, const char* uri, const char* payload, LSFilterFunc callback,
+    void* ctx, LSMessageToken* ret_token, LSError* error);
+bool LSCallOneReply(LSHandle* sh, const char* uri, const char* payload, LSFilterFunc callback,
+    void* ctx, LSMessageToken* ret_token, LSError* error);
+bool LSCallCancel(LSHandle* sh, LSMessageToken token, LSError* error);