Split safety into (llama-guard, prompt-guard, code-scanner) (#400)

Splits the meta-reference safety implementation into three distinct providers:

- inline::llama-guard
- inline::prompt-guard
- inline::code-scanner

Note that this PR is a backward incompatible change to the llama stack server. I have added deprecation_error field to ProviderSpec -- the server reads it and immediately barfs. This is used to direct the user with a specific message on what action to perform. An automagical "config upgrade" is a bit too much work to implement right now :/

(Note that we will be gradually prefixing all inline providers with inline:: -- I am only doing this for this set of new providers because otherwise existing configuration files will break even more badly.)

llama_stack/providers/inline/safety/code_scanner/code_scanner.py

@@ -0,0 +1,58 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
+from typing import Any, Dict, List
+
+from llama_models.llama3.api.datatypes import interleaved_text_media_as_str, Message
+from termcolor import cprint
+
+from .config import CodeScannerConfig
+
+from llama_stack.apis.safety import *  # noqa: F403
+
+
+class MetaReferenceCodeScannerSafetyImpl(Safety):
+    def __init__(self, config: CodeScannerConfig, deps) -> None:
+        self.config = config
+
+    async def initialize(self) -> None:
+        pass
+
+    async def shutdown(self) -> None:
+        pass
+
+    async def register_shield(self, shield: Shield) -> None:
+        if shield.shield_type != ShieldType.code_scanner:
+            raise ValueError(f"Unsupported safety shield type: {shield.shield_type}")
+
+    async def run_shield(
+        self,
+        shield_id: str,
+        messages: List[Message],
+        params: Dict[str, Any] = None,
+    ) -> RunShieldResponse:
+        shield = await self.shield_store.get_shield(shield_id)
+        if not shield:
+            raise ValueError(f"Shield {shield_id} not found")
+
+        from codeshield.cs import CodeShield
+
+        text = "\n".join([interleaved_text_media_as_str(m.content) for m in messages])
+        cprint(f"Running CodeScannerShield on {text[50:]}", color="magenta")
+        result = await CodeShield.scan_code(text)
+
+        violation = None
+        if result.is_insecure:
+            violation = SafetyViolation(
+                violation_level=(ViolationLevel.ERROR),
+                user_message="Sorry, I found security concerns in the code.",
+                metadata={
+                    "violation_type": ",".join(
+                        [issue.pattern_id for issue in result.issues_found]
+                    )
+                },
+            )
+        return RunShieldResponse(violation=violation)