chore(apple/M1): move widget sources into the Xcode target's synced folder

Xcode created the PunktfunkWidgetsExtension target with a file-system-
synchronized root group at clients/apple/PunktfunkWidgets/, so the target
compiles whatever lives there. Deleted the three generated stubs
(PunktfunkWidgets.swift / PunktfunkWidgetsBundle.swift /
PunktfunkWidgetsControl.swift — the stub @main WidgetBundle would collide with
ours) and moved our sources (PunktfunkWidgetBundle / HostsWidget /
SessionLiveActivity) from Sources/PunktfunkWidgets/ into PunktfunkWidgets/. Kept
the generated Info.plist (build-excluded via the sync exception set) and
Assets.xcassets. Still outside Sources/, so SwiftPM ignores it; swift build green.

project.pbxproj is intentionally NOT part of this commit — the target's
capability/signing edits (step 3) are still in progress in Xcode.

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

clients/apple/PunktfunkWidgets/Info.plist

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>NSExtension</key>
+	<dict>
+		<key>NSExtensionPointIdentifier</key>
+		<string>com.apple.widgetkit-extension</string>
+	</dict>
+</dict>
+</plist>