[Shubham-Padkonde]

Summary:

Fixes #59327.

RawPropsParser keeps property names after preparation, but its string views can refer to temporary names. In particular, RawProps::at(name, prefix, suffix) passes a view into a local concatenated string. Later duplicate checks and cursor lookups read that string after it has been destroyed.

Store owned strings in the parser and construct each stored key when it is first registered. Lookup still accepts string views; the copy happens during parser preparation. The key map already copies names into its own storage.

Changelog:

[GENERAL] [FIXED] - Retain property names used to prepare RawPropsParser so temporary and composed names remain valid during later lookups.

Test Plan:

Added two GoogleTest regressions covering short and long prefixes/suffixes, duplicate registration, repeated and out-of-order lookups, and temporary unprefixed names across vector growth.

Linux AddressSanitizer validation compiles the actual RawProps, RawPropsParser, RawPropsKeyMap and JSI sources with the new test file and React Native's Folly source configuration:

• ASAN_OPTIONS=detect_stack_use_after_return=1 build-rawprops/rawprops_tests: both tests pass.
• Restoring the two production files from base commit 54b5f22c33773a83de8fb6dc9a7091ba180842b4 and rebuilding makes each regression fail independently: stack-use-after-return for composed names and stack-use-after-scope for temporary names.
• clang-format 21.1.2 checks the new test file successfully; git diff --check passes.

The focused harness and its workflow are on a separate fork branch, outside this PR. Full Android/iOS builds and the full native suite were not run.

[javache]

RawProps.at is only supposed to be used with const char* args in constructor methods, for which I believe this is safe.

Changing string_view to string significantly changes the memory costs here, and we should avoid it.