[fern-autoversion] chore: add docstrings and field descriptions across model types

Add class-level docstrings and `pydantic.Field()` descriptions to
numerous model types throughout the SDK. These changes improve
developer experience via IDE tooltips and generated documentation
without altering any public API signatures, serialization behavior,
or runtime logic.

Key changes:
- Add class docstrings to ~30+ model types (e.g., `Assistant`, `Call`, `BackoffPlan`, `CompliancePlan`, `ConversationNode`, `CampaignPaginatedResponse`, etc.)
- Add `pydantic.Field(description=...)` annotations to previously bare field declarations across assistant, insight, credential, and tool models
- Update `User-Agent` header version string to Fern placeholder value

🌿 Generated with Fern

Author: fern-api[bot]

.fern/metadata.json

@@ -9,5 +9,5 @@
     "client_class_name": "Vapi"
   },
   "originGitCommit": "002f500c6453bab1abf000c45b51423240423e8e",
-  "sdkVersion": "0.0.0.dev0"
+  "sdkVersion": "2.0.1"
 }

pyproject.toml

@@ -4,7 +4,7 @@ dynamic = ["version"]
 
 [tool.poetry]
 name = "vapi_server_sdk"
-version = "0.0.0.dev0"
+version = "2.0.1"
 description = ""
 readme = "README.md"
 authors = []

src/vapi/core/client_wrapper.py

@@ -32,7 +32,7 @@ def get_headers(self) -> typing.Dict[str, str]:
             "X-Fern-Runtime": f"python/{platform.python_version()}",
             "X-Fern-Platform": f"{platform.system().lower()}/{platform.release()}",
             "X-Fern-SDK-Name": "vapi_server_sdk",
-            "X-Fern-SDK-Version": "0.0.0.dev0",
+            "X-Fern-SDK-Version": "2.0.1",
             **(self.get_custom_headers() or {}),
         }
         headers["Authorization"] = f"Bearer {self._get_token()}"