fix: crash on bad model_specs from audio.cpp, sanitized

1 files changed, 2 insertions, 2 deletions

diff --git a/app/docs/backend-audiocpp.md b/app/docs/backend-audiocpp.md
index 276bf08..32ce39b 100644
--- a/app/docs/backend-audiocpp.md
+++ b/app/docs/backend-audiocpp.md
@@ -6,13 +6,13 @@ The easiest way is the TUI: run `python audiobook.py`, choose **Configure Backen
 
 The hub's backend status table distinguishes how far audio.cpp is set up: `unavailable` (nothing present), `downloaded (not built)` (checkout cloned, `audiocpp_server` not installed), `built (not configured)` (binary installed, no `server.json`), `installed` (ready; or `installed (models missing)` when the config references undownloaded models), and `running` once its server answers. Whenever the checkout exists but `audiocpp_server` is missing, **Configure Backends… → Build audio.cpp Server** installs it from the TUI — asking whether to download the prebuilt release (recommended, macOS and Windows) or build from source (the wizard offers the same choice during setup), so a backend whose install you skipped is never stuck as "unavailable". On a fresh install the setup is one continuous flow: clone → configure → and then the install and the model downloads run **simultaneously** in a split view (half downloading/building, half downloading models). The setup steps are therefore ordered install > configure > download, and **Build audio.cpp Server** and **Download Missing Models (audio.cpp)** are never offered at the same time; **Build audio.cpp Server** downloads any missing models alongside the install, and **Download Missing Models (audio.cpp)** remains only as a fallback for when a download fails or is interrupted.
 
-Prebuilt installs are tracked with a `prebuilt.json` marker inside the build directory. **Update Backends** then skips the git pull/rebuild flow for those and instead re-downloads when upstream publishes a newer release (and checks the checkout out at the release's tag, keeping its model catalog and tooling in sync with the binary). A source-built checkout keeps updating by git pull + rebuild.
+Prebuilt installs are tracked with a `prebuilt.json` marker inside the build directory. **Update Backends** then skips the git pull/rebuild flow for those and instead re-downloads when upstream publishes a newer release (and checks the checkout out at the release's tag, keeping its model catalog and tooling in sync with the binary). When that re-download fails (usually GitHub's API rate limit), **Update Backends** falls back to the same source-build route a source-built checkout uses — the installed binary is only replaced once a new one is in place, so it keeps working meanwhile — and a successful fallback build removes the now-stale marker so later updates take the git + rebuild route. A source-built checkout keeps updating by git pull + rebuild.
 
 If you prefer to install the backend yourself (in your own environment, not the managed venv), the manual steps are below. Either way the hub detects a running server by its port, so a manually-installed backend works once its server is up.
 
 ### Download or build audiocpp_server
 
-The wizard's default on macOS and Windows is to download a prebuilt `audiocpp_server` from [audio.cpp's releases](https://github.com/0xShug0/audio.cpp/releases) (checksum-verified, ~20–25 MB, no compiler or Xcode required — on Intel Macs the release runs on CPU only, and Windows CUDA builds come in 12.4/13.3 variants picked to match your NVIDIA driver). The newest version is resolved without GitHub's API, so the check rarely hits the API's rate limit; if the API *is* rate-limited when a download starts, the install proceeds without checksum verification (with a loud warning). If the download still fails, the TUI does not leave you half-installed: the same Build lane automatically falls back to building from source (a cancelled download, or an explicit `--prebuilt yes` — which exists to forbid source builds — do not fall back). **Update Backends** keeps a prebuilt install current automatically. The manual build steps, if you prefer building from source, are below — build for your platform and backend `(cuda, vulkan, hip, cpu)`. Check [audio.cpp's readme](https://github.com/0xShug0/audio.cpp) for details. audio.cpp ships one helper script per platform, and the hub runs the one matching your OS:
+The wizard's default on macOS and Windows is to download a prebuilt `audiocpp_server` from [audio.cpp's releases](https://github.com/0xShug0/audio.cpp/releases) (checksum-verified, ~20–25 MB, no compiler or Xcode required — on Intel Macs the release runs on CPU only, and Windows CUDA builds come in 12.4/13.3 variants picked to match your NVIDIA driver). The newest version is resolved without GitHub's API, so the check rarely hits the API's rate limit; if the API *is* rate-limited when a download starts, the install proceeds without checksum verification (with a loud warning). If the download still fails, the TUI does not leave you half-installed: the same Build lane automatically falls back to building from source (a cancelled download, or an explicit `--prebuilt yes` — which exists to forbid source builds — do not fall back). **Update Backends** keeps a prebuilt install current automatically, and falls back to a source build the same way when its re-download fails. The manual build steps, if you prefer building from source, are below — build for your platform and backend `(cuda, vulkan, hip, cpu)`. Check [audio.cpp's readme](https://github.com/0xShug0/audio.cpp) for details. audio.cpp ships one helper script per platform, and the hub runs the one matching your OS:
 
 ```bash
 # Linux