Add Tenstorrent Blackhole tt-nn port

SERVING.md

@@ -63,6 +63,33 @@ fastapi / uvicorn / pydantic / pillow; `runtime.packages` adds to that set.
 Despite the name, this kind is not diffusion-only -- `jashansinghTT/s2-pro-blackhole` is a
 TTS model using it. It simply means "the model's own ASGI app under uvicorn".
 
+## The catalog tags are automatic -- do not add them by hand
+
+`tt-model-cache`, `tt-model-container` and `tt-model-catalog` are written by the real flow,
+not by editing this card:
+
+| tag | written by | source |
+|---|---|---|
+| `tt-model-cache` | `package` | `TT_MODEL_TAG` in `tt_kernel/__init__.py:9` |
+| `tt-model-container` | `package` | `build.py:996` -- `{TT_MODEL_TAG, m.arch, m.kind, "tt-model-container"}` |
+| `blackhole`, `tt-dit-server`, `p150` | `package` | same line, from `arch` / `kind` / each profile's `hardware` |
+| `tt-model-catalog` | `--publish` | `cli.py:620` / `cli.py:820` |
+
+So finishing step 5 produces exactly the tag set the catalog models carry. Adding them to
+this repo now would be actively harmful, because **nothing validates them**:
+
+- `tt-model-cache` is what `tt-model search` filters on (`hub.py:268`), so the repo would
+  show up as an installable bundle and `tt-model pull` would then fail -- there is no
+  `tt_kernel_manifest.json` here, only the authoring `tt-model.yaml`.
+- `tt-model-container` asserts a v5.1 OCI image in `image/`, which does not exist yet.
+- `tt-model-catalog` lists it in the public community index, which renders each entry by
+  reading `tt_kernel_manifest.json`.
+- `tt-model publish <id>` does **not** check that the target is a real bundle -- it only
+  flips visibility and sets the tag -- so the guard rail you might expect is not there.
+
+Until the bundle is built, the honest tag set is the one this card already carries
+(`tenstorrent`, `blackhole`, `p150`, `ttnn`, `tt-metal`, plus the task tags).
+
 ## Known sharp edges (offline-validated, not yet hardware-validated)
 
 The manifest loads clean (`load_container_manifest(..., check_sources=False)` passes, which