feat(registry): make the Stack query providers for model listing (#2862)

This flips #2823 and #2805 by making the Stack periodically query the
providers for models rather than the providers going behind the back and
calling "register" on to the registry themselves. This also adds support
for model listing for all other providers via `ModelRegistryHelper`.
Once this is done, we do not need to manually list or register models
via `run.yaml` and it will remove both noise and annoyance (setting
`INFERENCE_MODEL` environment variables, for example) from the new user
experience.

In addition, it adds a configuration variable `allowed_models` which can
be used to optionally restrict the set of models exposed from a
provider.

docs/source/providers/inference/remote_fireworks.md

@@ -8,6 +8,7 @@ Fireworks AI inference provider for Llama models and other AI models on the Fire
 
 | Field | Type | Required | Default | Description |
 |-------|------|----------|---------|-------------|
+| `allowed_models` | `list[str \| None` | No |  | List of models that should be registered with the model registry. If None, all models are allowed. |
 | `url` | `<class 'str'>` | No | https://api.fireworks.ai/inference/v1 | The URL for the Fireworks server |
 | `api_key` | `pydantic.types.SecretStr \| None` | No |  | The Fireworks.ai API Key |
 

docs/source/providers/inference/remote_ollama.md

@@ -9,8 +9,7 @@ Ollama inference provider for running local models through the Ollama runtime.
 | Field | Type | Required | Default | Description |
 |-------|------|----------|---------|-------------|
 | `url` | `<class 'str'>` | No | http://localhost:11434 |  |
-| `refresh_models` | `<class 'bool'>` | No | False | refresh and re-register models periodically |
-| `refresh_models_interval` | `<class 'int'>` | No | 300 | interval in seconds to refresh models |
+| `refresh_models` | `<class 'bool'>` | No | False | Whether to refresh models periodically |
 
 ## Sample Configuration
 

docs/source/providers/inference/remote_together.md

@@ -8,6 +8,7 @@ Together AI inference provider for open-source models and collaborative AI devel
 
 | Field | Type | Required | Default | Description |
 |-------|------|----------|---------|-------------|
+| `allowed_models` | `list[str \| None` | No |  | List of models that should be registered with the model registry. If None, all models are allowed. |
 | `url` | `<class 'str'>` | No | https://api.together.xyz/v1 | The URL for the Together AI server |
 | `api_key` | `pydantic.types.SecretStr \| None` | No |  | The Together AI API Key |
 

docs/source/providers/inference/remote_vllm.md

@@ -13,7 +13,6 @@ Remote vLLM inference provider for connecting to vLLM servers.
 | `api_token` | `str \| None` | No | fake | The API token |
 | `tls_verify` | `bool \| str` | No | True | Whether to verify TLS certificates. Can be a boolean or a path to a CA certificate file. |
 | `refresh_models` | `<class 'bool'>` | No | False | Whether to refresh models periodically |
-| `refresh_models_interval` | `<class 'int'>` | No | 300 | Interval in seconds to refresh models |
 
 ## Sample Configuration