feat: connected devices sync, unified queue, scrobbling, v1.2

- Unified queue model: replace history/queue split with tracks[]+currentIndex
- Connected devices: fix Mac not pausing when another device becomes active
- Fix applyFullState playing wrong track (stale currentTrack reference)
- Fix seek in client mode (use `time` field per web client convention)
- Fix seek UI snapping back with optimistic seek override
- Add play count scrobbling via POST /api/player/history
- Playlists tab auto-loads on switch (no retry button needed)
- Fix share button to copy proper server-based track URL
- Device icon color: primary when active, accent when remote
- Full queue transfer between devices via transfer_state command
- Bump version to 1.2

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

furumi_macos.xcodeproj/project.pbxproj

@@ -409,7 +409,7 @@
 					"$(inherited)",
 					"@executable_path/../Frameworks",
 				);
-				MARKETING_VERSION = 1.0;
+				MARKETING_VERSION = 1.2;
 				PRODUCT_BUNDLE_IDENTIFIER = "hexor.furumi-macos";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				REGISTER_APP_GROUPS = YES;
@@ -442,7 +442,7 @@
 					"$(inherited)",
 					"@executable_path/../Frameworks",
 				);
-				MARKETING_VERSION = 1.0;
+				MARKETING_VERSION = 1.2;
 				PRODUCT_BUNDLE_IDENTIFIER = "hexor.furumi-macos";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				REGISTER_APP_GROUPS = YES;