* Replace standalone Studio wording with Unsloth
Replace the single word Studio with Unsloth wherever it is used as
shorthand for Unsloth Studio in docs, CLI output, UI strings, i18n
locales, workflow display names, comments and docstrings.
Kept unchanged: the full name Unsloth Studio, third party product
names (LM Studio, Visual Studio, Mac Studio), feature names
(Recipe Studio, Fine-tuning Studio and its translations), and all
identifiers such as env vars, commands, paths and filenames.
* Address review feedback on the Studio wording rename
Use "an" before Unsloth where the rename left the article as "a".
Restore the split brand where Unsloth and Studio render as two halves
of the full product name: the onboarding sidebar subtitle and the
IPv6 localhost warning. Scope two messages to the full name Unsloth
Studio where plain Unsloth was misleading: the AMD README bullet and
the CLI studio setup error.
Make macOS llama.cpp prebuilt selection host-OS-version aware: skip a prebuilt whose minimum-OS exceeds the host and walk back to the newest release that loads (macOS 26 keeps latest; 14/15 land on a compatible older release). Source-build fallback pins CMAKE_OSX_DEPLOYMENT_TARGET=13.3. CI: binary-load assertion plus a macos-14/15/26 install matrix. No change to Linux/Windows or CUDA selection.
