chore!: remove model mgmt from CLI for Hugging Face CLI (#3700)

This change removes the `llama model` and `llama download` subcommands
from the CLI, replacing them with recommendations to use the Hugging
Face CLI instead.

Rationale for this change:
- The model management functionality was largely duplicating what
Hugging Face CLI already provides, leading to unnecessary maintenance
overhead (except the download source from Meta?)
- Maintaining our own implementation required fixing bugs and keeping up
with changes in model repositories and download mechanisms
- The Hugging Face CLI is more mature, widely adopted, and better
maintained
- This allows us to focus on the core Llama Stack functionality rather
than reimplementing model management tools

Changes made:
- Removed all model-related CLI commands and their implementations
- Updated documentation to recommend using `huggingface-cli` for model
downloads
- Removed Meta-specific download logic and statements
- Simplified the CLI to focus solely on stack management operations

Users should now use:
- `huggingface-cli download` for downloading models
- `huggingface-cli scan-cache` for listing downloaded models

This is a breaking change as it removes previously available CLI
commands.

Signed-off-by: Sébastien Han <seb@redhat.com>

pyproject.toml

@@ -25,14 +25,13 @@ classifiers = [
 ]
 dependencies = [
     "aiohttp",
-    "fastapi>=0.115.0,<1.0",                  # server
-    "fire",                                   # for MCP in LLS client
+    "fastapi>=0.115.0,<1.0",                          # server
+    "fire",                                           # for MCP in LLS client
     "httpx",
-    "huggingface-hub>=0.34.0,<1.0",
     "jinja2>=3.1.6",
     "jsonschema",
     "llama-stack-client>=0.2.23",
-    "openai>=1.107",                                # for expires_after support
+    "openai>=1.107",                                  # for expires_after support
     "prompt-toolkit",
     "python-dotenv",
     "python-jose[cryptography]",
@@ -43,13 +42,13 @@ dependencies = [
     "tiktoken",
     "pillow",
     "h11>=0.16.0",
-    "python-multipart>=0.0.20",               # For fastapi Form
-    "uvicorn>=0.34.0",                        # server
-    "opentelemetry-sdk>=1.30.0",              # server
+    "python-multipart>=0.0.20",                       # For fastapi Form
+    "uvicorn>=0.34.0",                                # server
+    "opentelemetry-sdk>=1.30.0",                      # server
     "opentelemetry-exporter-otlp-proto-http>=1.30.0", # server
-    "aiosqlite>=0.21.0",                      # server - for metadata store
-    "asyncpg",                                # for metadata store
-    "sqlalchemy[asyncio]>=2.0.41",           # server - for conversations
+    "aiosqlite>=0.21.0",                              # server - for metadata store
+    "asyncpg",                                        # for metadata store
+    "sqlalchemy[asyncio]>=2.0.41",                    # server - for conversations
 ]
 
 [project.optional-dependencies]
@@ -68,14 +67,14 @@ dev = [
     "pytest-cov",
     "pytest-html",
     "pytest-json-report",
-    "pytest-socket", # For blocking network access in unit tests
-    "nbval", # For notebook testing
+    "pytest-socket",       # For blocking network access in unit tests
+    "nbval",               # For notebook testing
     "black",
     "ruff",
     "types-requests",
     "types-setuptools",
     "pre-commit",
-    "ruamel.yaml", # needed for openapi generator
+    "ruamel.yaml",         # needed for openapi generator
 ]
 # These are the dependencies required for running unit tests.
 unit = [
@@ -141,9 +140,7 @@ docs = [
     "requests",
 ]
 codegen = ["rich", "pydantic>=2.11.9", "jinja2>=3.1.6"]
-benchmark = [
-    "locust>=2.39.1",
-]
+benchmark = ["locust>=2.39.1"]
 
 [project.urls]
 Homepage = "https://github.com/llamastack/llama-stack"
@@ -242,7 +239,6 @@ follow_imports = "silent"
 # to exclude the entire directory.
 exclude = [
     # As we fix more and more of these, we should remove them from the list
-    "^llama_stack/cli/download\\.py$",
     "^llama_stack.core/build\\.py$",
     "^llama_stack.core/client\\.py$",
     "^llama_stack.core/request_headers\\.py$",
@@ -332,6 +328,4 @@ classmethod-decorators = ["classmethod", "pydantic.field_validator"]
 [tool.pytest.ini_options]
 addopts = ["--durations=10"]
 asyncio_mode = "auto"
-markers = [
-    "allow_network: Allow network access for specific unit tests",
-]
+markers = ["allow_network: Allow network access for specific unit tests"]