fix: Address reviewer feedback on CHANGELOG placement and Swift stub

- Move the SPM/xcframework entry out of the already-released `## 8.17.0`
  section into a new `## Unreleased` section (danger check). The merge
  from main pulled 8.17.0's release notes on top and swept the entry
  inside them.

- Add a private constant to RNSentrySwiftLinkStub.swift. A pure-comment
  Swift file compiles to nothing, which would defeat the whole reason
  for the stub (forcing Xcode to link Swift runtime compatibility libs
  when consuming Sentry.xcframework's static Swift symbols).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: alwx

CHANGELOG.md

@@ -6,6 +6,16 @@
 > make sure you follow our [migration guide](https://docs.sentry.io/platforms/react-native/migration/) first.
 <!-- prettier-ignore-end -->
 
+## Unreleased
+
+### Changes
+
+- Consume `sentry-cocoa` as a prebuilt xcframework by default on iOS ([#6381](https://github.com/getsentry/sentry-react-native/pull/6381))
+
+  **Warning**
+
+  **This may be a breaking change for some setups.** `pod install` now downloads `Sentry.xcframework` from sentry-cocoa's GitHub release (SHA256-verified) and vendors it, instead of building Sentry from source as a CocoaPod. If your iOS build breaks after upgrading (e.g. when another pod also depends on the `Sentry` CocoaPod), or if your `pod install` environment cannot reach `github.com`, set `SENTRY_USE_XCFRAMEWORK=0` before `pod install` to restore the previous source-build behavior.
+
 ## 8.17.2
 
 ### Fixes
@@ -48,11 +58,6 @@
 ### Changes
 
 - Default `mobileReplayIntegration({ networkCaptureBodies })` to `true`, matching the iOS and Android native SDK defaults ([#6372](https://github.com/getsentry/sentry-react-native/pull/6372))
-- Consume `sentry-cocoa` as a prebuilt xcframework by default on iOS ([#6381](https://github.com/getsentry/sentry-react-native/pull/6381))
-
-  **Warning**
-
-  **This may be a breaking change for some setups.** `pod install` now downloads `Sentry.xcframework` from sentry-cocoa's GitHub release (SHA256-verified) and vendors it, instead of building Sentry from source as a CocoaPod. If your iOS build breaks after upgrading (e.g. when another pod also depends on the `Sentry` CocoaPod), or if your `pod install` environment cannot reach `github.com`, set `SENTRY_USE_XCFRAMEWORK=0` before `pod install` to restore the previous source-build behavior.
 
 ### Fixes
 

packages/core/ios/RNSentrySwiftLinkStub.swift

@@ -5,3 +5,8 @@
 // target itself contains Swift code — without this stub, linking a dynamic
 // RNSentry framework fails with:
 //   Undefined symbols: "__swift_FORCE_LOAD_$_swiftCompatibility56"
+
+// A private, unused constant so the compiler emits a real object file. A
+// pure-comment file compiles to nothing and would defeat the purpose of
+// the stub.
+private let _rnSentrySwiftLinkStub: Void = ()