chore(apple): Xcode 27 project upgrade + hardened runtime

Applied via Xcode's recommended-settings upgrade and distribution prep:
- LastUpgradeCheck / scheme LastUpgradeVersion 2650 -> 2700.
- DEVELOPMENT_TEAM (F4H37KF6WC) hoisted to the project-level build configs; the
  now-redundant per-target copies are dropped (all targets inherit it).
- ENABLE_HARDENED_RUNTIME = YES on the macOS app target (required for Developer ID
  notarization). Signing stays Apple Development + Config/Punktfunk.entitlements.

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

clients/apple/Punktfunk.xcodeproj/xcshareddata/xcschemes/Punktfunk-iOS.xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "2650"
+   LastUpgradeVersion = "2700"
    version = "1.7">
    <BuildAction
       parallelizeBuildables = "YES"

clients/apple/Punktfunk.xcodeproj/xcshareddata/xcschemes/Punktfunk-tvOS.xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "2650"
+   LastUpgradeVersion = "2700"
    version = "1.7">
    <BuildAction
       parallelizeBuildables = "YES"

clients/apple/Punktfunk.xcodeproj/xcshareddata/xcschemes/Punktfunk.xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "2650"
+   LastUpgradeVersion = "2700"
    version = "1.7">
    <BuildAction
       parallelizeBuildables = "YES"