perf: strip local symbols from the release framework, log decodable native backtraces - #556

What

1. Strip local symbols from the release NativeScript.framework (STRIP_STYLE = non-global on the NativeScript target's Release configuration). Archives only stripped debug symbols before, so every release shipped ~24k local symbols, mostly V8 private externs.
2. Make native backtraces decodable. tns::LogBacktrace now prints each frame's image and load address + offset (crash-report layout), and ends with a Binary images: list giving each image's load address, arch, UUID and path.
3. Docs: new docs/native-stack-traces.md (reading a trace, where to get the runtime's dSYM, resolving frames with atos, what crash reporters need), linked from the docs index and from the crash-reporter section of error-handling.md.

Why

App size. The iOS device slice goes from 15.75 MB to 13.04 MB (−2.7 MB per app). This came out of the third-party shopbench comparison, where NativeScript 9.1.0 had the largest .app (47.2 MB). Most of that gap is the default metadata already removed by #488; this is the next biggest lever on the framework itself.

Stripping makes dladdr return the nearest exported symbol for internal functions, which names the wrong function: an internal v8::internal::CppHeap::CollectGarbage frame would print as v8::CppHeap::CollectGarbageInYoungGenerationForTesting + 8048. That's why (2) is part of this PR: the image offset and UUID are exact, and atos with the matching dSYM recovers the real name, file and line.

Example of the new output:

Native stack trace:
1   NativeScript                          0x104ca2088 0x104a00000 + 2760840 v8::CppHeap::CollectGarbageInYoungGenerationForTesting(cppgc::EmbedderStackState) + 8048
2   NativeScript                          0x104b1ee7c 0x104a00000 + 1175164 tns::ModuleInternal::RunModule(v8::Isolate*, std::__1::basic_string<char, ...>) + 92
Binary images:
0x104a00000 NativeScript arm64 <03DD4E84-EE0C-3280-AF5D-5CC4087BB5A5> .../MyApp.app/Frameworks/NativeScript.framework/NativeScript

atos -o NativeScript.framework.dSYM -arch arm64 -l 0x104a00000 0x104ca2088 0x104b1ee7c
# v8::internal::CppHeap::CollectGarbage(cppgc::internal::GCConfig) (in NativeScript) + 64
# tns::ModuleInternal::RunModule(...) (in NativeScript) (ModuleInternal.mm:217)

Safety of stripping

• strip -x / non-global removes only local symbols. The export trie and imports are unchanged: the stripped binary exports the same 3,548 symbols as an unstripped build of this commit. Compared with the published 9.1.0-next.2026-11-05 build, the only differences are API changes merged since (feat(runtime): ns:interop builtin modules, global interop as compat #527, perf(runtime): skip unread BroadcastChannel deliveries and let idle channels be collected #543, fix(inspector): serve source map streams the way Chromium does #548).
• dlsym can only see exported symbols, so FFI (SymbolLoader), the runtime's own dlsym calls and plugins linking against v8::/tns:: symbols are unaffected. ObjC lookups go through runtime metadata, not the symbol table.
• Xcode strips at install time, after dsymutil, so the dSYM keeps every name and its UUID still matches the binary (checked: atos resolves internal V8 functions against the new dSYM).
• Debug builds (local development, the test suite) keep every symbol.

Testing

• ./build_nativescript.sh --no-catalyst --no-sim --no-vision: device slice has 0 local symbols, 13,035,104 bytes; dSYM UUID matches; exports compared as above.
• ./run_tests.sh --temp-sim: 1865 specs, 0 failures, 11 skipped. (The suite builds Debug, so it covers the new LogBacktrace compiling and the runtime as a whole, not the stripped binary.)
• The suite never calls LogBacktrace, so the output was checked by compiling the exact function text from Helpers.mm into a dylib, stripping it with strip -x, and resolving the printed frames with atos against its dSYM. Both the load-address and the -l 0x0 <offset> forms resolved the stripped internal frame to the right function and line. arm64e is reported correctly for system images such as dyld.
• The commands in docs/native-stack-traces.md were run against the published v9.1.0-next.2026-11-05-42101299477 dSYM and give the documented output.

Not covered

• Whether Xcode copies the runtime's dSYM from the SwiftPM xcframework into an app's .xcarchive (relevant for App Store Connect and crash-reporter symbolication) was not tested here. A production app's deploys suggest it does: the only dSYMs it uploads to its crash reporter come from the archive, and NativeScript frames in its crash reports resolve to file and line. That is one app's Xcode setup, not a range of Xcode versions, so the docs still point at the release assets and the xcframework's dSYMs/ folder rather than promising the archive has it.
• TKLiveSync was left alone (73 local symbols).

Summary by CodeRabbit

• New Features
  • Native stack traces now include image names, addresses, load addresses, offsets, and architecture and UUID details when available.
• Documentation
  • Added guidance on interpreting native stack traces in release builds, matching dSYMs, resolving frames, and sharing symbols with crash-reporting services.
  • Expanded error-handling guidance on limitations of stack symbols and options for symbolication.